Sunday

April 20, 2014

April 20, 2014

Number of results: 219,739

**calculus**

the graph can be seen here: http://www.wolframalpha.com/input/?i=plot+y%3D|x^2+%2Bx-2|+for+-4+%3C%3D+x+%3C%3D+3 That should make it easy to answer the other questions. If not, come on back and show where you get stuck.
*Friday, February 28, 2014 at 3:32am by Steve*

**math 1**

write it this way: c^2 - 6cd + 9d^2 - 4 = (c - 3d)^2 - 4 now I see a difference of squares = (c-3d + 2)(c-3d-2)
*Monday, November 8, 2010 at 3:09pm by Reiny*

**math**

r = 3d/4, or 4r = 3d r/2 / (3d/4 + r/2) = 2r/(3d+2r) = 2r/6r = 1/3 check: If Roberto has 12 cards, David has 16 After Robert gives David 6, 6/18 = 1/3
*Monday, January 28, 2013 at 11:50pm by Steve*

**Math**

Probably quite easy but I am stuck :/ 3d+6e
*Friday, June 18, 2010 at 11:29am by Eloise*

**Substitution Method in Algebra**

4c= 3d+3 , but you also told me c = d-1 so.. 4(d-1) = 3d+3 4d - 4 = 3d + 3 4d - 3d = 3 + 4 d = 7 sub that back into c=d-1 c = 7-1 = 6
*Wednesday, November 12, 2008 at 9:06pm by Reiny*

**math**

d = number of dimes 3d = number of nickels d + 3d = 1.50 simplify and solve the equation for d and 3d
*Saturday, April 20, 2013 at 1:55pm by rbowh*

**arthmetic**

13th term is 27 --- a + 12d = 27 the 7th iterm is 3 times the 2nd term --> a+6d = 3(a+d) or a+6d = 3a + 3d 2a = 3d a = 3d/2 sub into the first equation 3d/2 + 12d = 27 3d+24d=54 d = 2 then a = 3(2)/2 = 3 I will let you finish it for the sum, you did not say how many terms ...
*Wednesday, October 12, 2011 at 5:06am by Reiny*

**CHRIST MATH**

I will assume that AP stands for arithmetic progression so you are given: a + (a+d) + (a+2d) + (a+3d) = 20 4a + 6d = 20 2a + 3d = 10 product of 1st and 4th = a(a+3d) product of 2nd to 3rd = (a+d)(a+2d) then: a(a+3d)/( (a+d)(a+2d) ) = 2/3 (a^2 + 3ad)/(a^2 + 3ad + 2d^2) = 2/3 3a...
*Tuesday, March 12, 2013 at 7:01am by Reiny*

**MATH HELP!!**

from the 2nd: 2c + 6d = -34 c + 3d = -17 c = -3d-17 plug into the 1st: 3(-3d-17) - 7d = -3 -9d - 51 - 7d = -3 -16d = 48 d = -3 then c = -3(-3) - 17 = -8 c = -8 , d = -3
*Sunday, March 23, 2014 at 1:49pm by Reiny*

**chemistry**

I'm not sure what you mean by explain. I assume you are talking about the 3d series (there are several transition series; i.e., 3d, 4d, 5d, 4f, etc)The easy way to remember the electron configuration for the 3d series is this. The number of electrons in the 3d orbitals will ...
*Tuesday, August 30, 2011 at 9:15pm by DrBob222*

**Math**

8d^2 + 3d + 7d^2 - 6d 15d^2 - 3d
*Saturday, August 20, 2011 at 5:21pm by Ms. Sue*

**math**

The (n+1)st term is a+nd a+3d=-6 a+10d = -34 subtract to get 7d = -28 having d, now you can get a, since a+3d = -6
*Tuesday, February 19, 2013 at 3:15pm by Steve*

**Math: Check Answers**

1. How can this product be simplified? 5x^2(2x – 3) 5x^2 + 2x – 3 10x^3 – 15x^2 –5x^2 7x^3 – 15x^2 2. What is the GCF of the terms of 8c^3 + 12c^2 + 10c ? 2 4 2c 4c 3. How can the polynomial 6d^4 + 9d^3 – 12d^2 be factored? 3d^2(2d^2 + 3d – 4) 3d^2(3d^2 + 6d – 9) 3d(d^3 + 3d^2...
*Tuesday, January 29, 2013 at 11:08am by Deborah *

**Algebra 1--Three Word Problems (Reiny or Kuai)**

#2. 30p+15c <= 150 #3. 0 <= m <= 45 0 <= a <= 50 4m + 3a >= 300 see the solution at http://www.wolframalpha.com/input/?i=solve+0+%3C%3D+m+%3C%3D+45%2C+0+%3C%3D+a+%3C%3D+50%2C+4m+%2B+3a+%3E%3D+300
*Friday, January 17, 2014 at 11:57am by Steve*

**MATH!!!**

Fist you use the distributive property method. 3(d+12)=8-4d 3d+36=8-4d Subtract 8 from each side 3d+28=-4d Subtract 3d from both sides 28=-7d divide by -7 from each side ?= d
*Sunday, January 13, 2013 at 11:56am by Emma*

**Math**

did you sketch it? did you get something like http://www.wolframalpha.com/input/?i=plot+y+%3D+%7Cx%7C%2B1+%2C+y+%3D+5 notice that they intersect at (4,5) and (-4,5) ? and the altitude is 4, and the base is 8 Area = (1/2)(8)(4) = 16
*Friday, December 20, 2013 at 7:57pm by Reiny*

**can't figure it out**

-3d+1/3(6+3d)=-10 -3d + 2+d =-10 -2d=-12 d=6 -3d+2+d= -10 -2d+2= -10 just thought this step should be shown :) -2d= -12 d=6
*Wednesday, November 15, 2006 at 9:19pm by garrett*

**CHEM**

What is the hybridization of the central atom in COH2?? Would the correct response, out of the following: a) sp b) sp^2 c) sp^3 d) sp^3d e) sp^3d^2 "e"-> sp^3d^2??
*Monday, November 26, 2007 at 11:31am by K*

**math**

plan1 = 1995 + 31m plan2 = 4095 + 16m plan3 = 8095 investigate the 3 equations, I let good ol' dependable Wolfram sketch them for you http://www.wolframalpha.com/input/?i=plot+y+%3D+1995+%2B+31m%2C+y+%3D+4095+%2B+16m%2C+y+%3D+8095 note that the plan3 is just a horizontal ...
*Sunday, September 29, 2013 at 5:21am by Reiny*

**English**

1. He is riding a roller board. 2. He is in the air on the roller board with his arms spread in the picture. 3. Talk with your partner and check the Yes box if your partner likies the activity. If your partner doesn't like the activity, check the no box. 4. He is watching a 3D...
*Sunday, April 14, 2013 at 3:50pm by rfvv*

**intermediate algebra**

Dal takes d Kim takes k Dal&Kim take b (for both) 1/b = 1/d + 1/k 1/(3/2) = 1/d + 1/(d+4) 2/3 = 1/d + 1/(d+4) multiply through by 3d(d+4) to get 2d(d+4) = 3(d+4) + 3d 2d^2 + 8d = 3d + 12 + 3d 2d^2 + 2d - 12 = 0 d^2 + d - 6 = 0 (d+3)(d-2) = 0 d = -3 or 2 must have positive time...
*Wednesday, April 25, 2012 at 10:33am by Steve*

**English**

Posted by rfvv on Sunday, April 14, 2013 at 3:50pm. 1. He is riding a roller board. 2. He is in the air on the roller board with his arms spread in the picture. 3. Talk with your partner and check the Yes box if your partner likies the activity. If your partner doesn't like ...
*Sunday, April 14, 2013 at 11:24pm by rfvv*

**maths**

3 dimensional shapes What about them? Do you need examples? A sphere is one. You can think of others. 3D shapes are figures that pop out. Like for example, if you saw an airplane fly by your're seeing it in 3D. But if you see an airplane on a piece of paper drawn by a third ...
*Saturday, November 11, 2006 at 4:31am by sam*

**algebra**

4(3d-2)=3d-5 12d - 8 = 3d - 5 12d - 3d = 5 + 8 9d = 13 d = 13/9 = 1 4/9
*Wednesday, October 17, 2012 at 8:31pm by Ms. Sue*

**Calculus**

look at the solution I just gave catlyn in the previous post compare your graph with hers http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E4+%2C+y+%3D+x neat eh?
*Sunday, December 15, 2013 at 2:14am by Reiny*

**math**

3 ducks and 1 chick cost the same as 2 geese. one duck, 2 chicks, and 3 geese cost $25. what is the price of each? i get: 3d+c=2g d+2c+3g=$25 i'm stuck from there. is there something missing? thanks in advance for any help.
*Monday, March 23, 2009 at 9:38pm by ken*

**calc**

intersection: x^4 = -x x^4 + x = 0 x(x^3 +1) = 0 x(x+1)(x^2 -x + 1)= 0 2 real solutions, x = 0 or x = -1 http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E4+%2C+y+%3D+-x area = ∫(-x - x^4) from -1 to 0 = [- x^2/2 - x^5/5] form -1 to 0 = (0 - (-1 -(-1)/5) = 1 - 1/5 = 4/5
*Sunday, December 15, 2013 at 2:10am by Reiny*

**CHEM**

The only thing I can tell you, without quantum mechanics and all the higher math that entails (which I can't do anyway), is that the 4s level is lower than the 3d when that electron goes into the 4s instead of the 3d.
*Wednesday, December 10, 2008 at 4:51pm by DrBob222*

**Caculus f'(x)**

y = ax^3 y' = 3ax^2 at x=-2, y' = 12a The line y=2x+b has slope 2, so 12a=2 a = 1/6 at x = -2, y = -8a = -4/3 so the line must go through (-2,-4/3) So, the tangent line has slope 2 and goes through (-2,-4/3) y = 2x+b -4/3 = -4 + b b = 8/3 So, now we have y = 2x - 8/3 is ...
*Friday, February 14, 2014 at 7:48pm by Steve*

**Math**

Solve the equation for d 0.2(d-6)=0.3d+5-3+0.1d I had d=-16 Work: 1. distribute 2. 0.2d-1.2=0.3d+5-3+0.1d 3. 0.2d=0.4d+3.2 4. -0.2d=3.2 5. divide 6. d= -16 I even did a check 0.2(d-6)=0.3d+5-3+0.1d 0.2(-16-6)=0.3(-16)+5-3+0.1(-16) 0.2(-22)=0.3(-16)+5-3+0.1(-16) -4.4=-4.4 Is ...
*Sunday, October 13, 2013 at 2:35pm by B8*

**Math**

Using the example: (a+b)(a+b)= a squared -b squared, we are asked to multiply and simplify (b+3d)(b-3d). Hint: Do not use distributive property. Shouldn't the answer be b squared - 9d squared?
*Thursday, June 3, 2010 at 7:10am by anonymous*

**Math Algr.2**

3(3d+4) - (3d-2) = 38 9 d + 12 - 3 d + 4 = 38 6 d + 16 = 38 6 d = 22 d = 11/3
*Wednesday, August 29, 2012 at 7:10pm by Damon*

**arithmetic**

term(3) = a+2d term(8) = a+7d a+7d = 5(a+2d) a+7d = 5a + 10d -4a = 3d a = -3d/4 in the same way a+6d = (a+3d) + 9 3d = 9 d = 3 then a = -9/4 first 5 terms are: -9/4, 3/4, 15/4, 27/4, 39/4 or -2.25, .75 , 3.75, 6.75, 9.75 check: term(8) = 18.75 term(3) = 3.75 what is 5(3.75) ? ...
*Friday, November 4, 2011 at 6:17am by Reiny*

**math**

probably did not get the correct graph because you skipped the brackets If you entered the equation as y = x/x-7 , you got a straight horizontal line at y = -6 because y = x/x - 7 = 1-7 = -6 You MUST include brackets, such as y = x/(x-7) http://www.wolframalpha.com/input/?i=...
*Sunday, December 15, 2013 at 12:56pm by Reiny*

**math**

let the sequence be 15 , 15+d, 15+2d, 15+3d, and 17 then 17 - (15+3d) = d 17 - 15 - 3d = d -4d = -2 d = 1/2 or .5 the inserted numbers are 15.5, 16, and 16.5
*Sunday, February 27, 2011 at 6:48am by Reiny*

**Math**

I'm learning series and sequences (grade 11). Please check that my steps show I understand what I'm doing/the concept and my answer as well: 5. The consecutive terms of an arithmetic sequences are 3.6, y, 8.2. Find the value of y. This seems to be a sequence question but I ...
*Tuesday, January 8, 2013 at 6:02pm by Crystal*

**Math**

multiply by 3 3d + 8 + 42=0 3d = -50 d = -50/3 if you meant: (d+8)/3 = -14 d+8 = -42 d = -50 see how important it is to insert brackets to establish the correct order of operation?
*Friday, March 9, 2012 at 10:11am by Reiny*

**math**

an=ao +n*d a2=ao+2d a6=ao+6d a3=ao+3d a4=ao+3d substutite all those, and find ao, and d.
*Tuesday, January 29, 2013 at 6:27pm by bobpursley*

**Math**

yes , the x-intercepts are 0 and 4, respectively confused about your second reply, the vertices are indeed (0,0) and (0,4) <<I mean 0 for -2x^2. Sorry about the 4, I didn't mean to put that. >> , don't even know what that is supposed to say. see, http://www....
*Tuesday, March 18, 2014 at 9:29pm by Reiny*

**Trig**

see the graphs here: http://www.wolframalpha.com/input/?i=plot+y%3Dcos2x+and+y%3D-2sinx However, it might be better to graph y = -cos2x, then the final graph would be easier to visualize: http://www.wolframalpha.com/input/?i=plot+y%3D+-cos2x+and+y%3D-2sinx%2C+y+%3D+-cos2x-...
*Sunday, March 30, 2014 at 1:03am by Steve*

**arithmetic progression**

Let d = the common difference t(n)=nth term t(6)-t(5)=d t(5)-t(4)=d t(4)-t(3)=d Add t(6)-t(3)=3d or 3d=12 Solve for the common difference d=4 Sum of the 2nd and 5th terms = 42 t(2)+t(5) =t(2)+(t(2)+3d) =2*t(2)+12 = 42 Solve for t(2) = 15 t(1) should be t(2)-1=15-4=11 and t(20...
*Friday, November 26, 2010 at 5:41am by MathMate*

**Algebra 2**

If I do my math right, we have for b=basic and d=deluxe construction: 2b+3d <= 36 assembly: 4b+3d <= 40 finishing: b + 2d <= 20 These graphs provide the intersection point b=8, d=4 so profit = 100b + 150d = 800 + 600 = 1400
*Tuesday, October 4, 2011 at 12:05am by Steve*

**calculus area between three curves**

3 graphs: y = 2√x y = 3 y = (-3/2)x + 7 see: http://www.wolframalpha.com/input/?i=plot++y+%3D+2√x+%2C+y+%3D+3+%2C+y+%3D+%28-3%2F2%29x+%2B+7+%2C+2%3Cx%3C3 intersection of y = (-3/2)x+7 and y = 2√x is aprr A(2.54, 3.188) intersection of y = 2√x and y = 3 ...
*Monday, December 2, 2013 at 2:12pm by Reiny*

**Algebra**

1/3(D+3)=5 1/3D + 1 = 5 1/3D = 4 D = 4/(1/3) D = 4 * (3/1) D = 12
*Sunday, October 17, 2010 at 6:12pm by Ms. Sue*

**Precalculus**

Since it is tangent at the origin, there has to be double root at (0,0). Also (3,0) is an x-intercept so we can let the equation be y = ax^2(x-3) but (1,4) lies on it 4 = a(1)(-2) a = -2 function is f(x) = -2x^2(x-3) expand if needed Proof: http://www.wolframalpha.com/input/?i...
*Tuesday, October 23, 2012 at 7:15pm by Reiny*

**CHEM**

For V3+ you took the three electrons from the 3d. You should take both 4s electrons plus 1 of the 3d electrons. The 4s orbital is further out than the 3d. I know what you are thinking about filling and how you filled it but V3+ will have 3d2 and no 4s. Go to www.webelements....
*Tuesday, November 13, 2007 at 10:14pm by DrBob222*

**Trig**

Why are you calling this trig ? x^2 - 4x + 2 = x+2 x^2 - 5x = 0 x(x-5) = 0 x = 0 or x = 5 sub in those x's in either of the two equations to find the y, then choose your answer. http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E2+–+4x+%2B+2%2C++y+%3D+x+%2B+2
*Friday, January 24, 2014 at 4:08pm by Reiny*

**Math**

3d(1-27d) = 0 3d = 0 therefore d = 0 1-27d = 0 -27d = -1 d = 1/27
*Wednesday, May 19, 2010 at 1:58pm by PsyDAG*

**Chemistry**

The orbitals, as we go OUT further from the nucleus: 1s 2s 2p 3s 3p 3d 4s 4p 3d and 4s are close to the same energy.
*Monday, March 16, 2009 at 10:07pm by DrBob222*

**middle school math**

3d + 2b = 1475 4d + b = 1550 I would change the second equation to b = 1550 - 4d and sub that into the first solve for d 3d + 2(1550-4d) = 1475 easy from here ....
*Friday, February 26, 2010 at 12:52am by Reiny*

**Chemistry (Need) 7:00**

What characterizes the electron configurations of transition metals such as silver and iron? Thanks Alot in Advance.. Fe is in the 3d transition series and Ag is in the 4d series. Thus, the distinguishing electron for the 3d series enters the 3d orbital while those for the 4d ...
*Sunday, November 12, 2006 at 11:23pm by Lance*

**arithmetic**

the sequence would be 5 , 5+d , 5+2d , 5+3d , .... , 5 + (n-2)d , 32 for n+2 terms 3rd mean = 4th term = a+3d 7th mean = 8th term = a + 7d but a = 5 (5+3d)/(5+7d) = 7/13 35 + 49d = 65 +39d 10d = 30 d = 30/10 = 3 so a + ((n+2)-1)d = 32 5 + (n+1)(3) = 32 3n+3 = 27 3n = 24 n = 8 ...
*Tuesday, May 14, 2013 at 1:45pm by Reiny*

**math**

Convert 5/8 to a decimal and you will see. http://www.google.com/#sclient=psy&hl=en&q=5%2F8+%3D&aq=&aqi=&aql=&oq=5%2F8+%3D&pbx=1&bav=on.2,or.&fp=ce4eb09fec0d07a5
*Wednesday, March 2, 2011 at 6:06am by drwls*

**algebra 2**

a(6)=a(1)+(6-1)d a(3)=a(1)+(3-1)d Subtract: a(6)-a(3)=3d 41-20=3d d=7 from which a(3)=a(1)+(3-1)7 a(1)=20-14=6
*Sunday, June 5, 2011 at 8:38pm by MathMate*

**calculus**

check your graph against this one: http://www.wolframalpha.com/input/?i=tan%28x%29+for+5pi%2F3+%3C%3D+x+%3C%3D+3pi
*Monday, February 24, 2014 at 3:12pm by Steve*

**math**

n = 3d 5n + 10d = 150 Substitute 3d for n in second equation and solve for d. Insert that value into the first equation and solve for n. Check by inserting both values into the second equation.
*Saturday, April 20, 2013 at 1:55pm by PsyDAG*

**math**

a+3d = 3 a+6d=36 subtract them: 3d = 33 d = 11 then a+33 = 3 a = -30 AP is -30 -19 -8 3 14 ... term(15) = a+14d = -30+14(11) = 124
*Saturday, February 18, 2012 at 12:43am by Reiny*

**Chem help**

That looks like 19 electrons to me (count them up) which means for the neutral element it must have 19 protons so look on the periodic table for element number 19. By the way, you KNOW it can't be Cr. Why? Cr is in the 3d transition series so it must have 3d electrons and this...
*Wednesday, October 17, 2012 at 11:41pm by DrBob222*

**Algebra 1 (Reiny)**

just graph the two lines as equations. Then, shade the region above the first, and below the 2nd. To check your answer, click here: http://www.wolframalpha.com/input/?i=solve+15p+%2B+10b+%3E%3D+90%2C+p%2Bb+%3C%3D+20
*Thursday, January 16, 2014 at 5:46pm by Steve*

**chemistry**

Ar is 18. Fe neutral atom is 26. Ar 3d^6 4s2 = 18 + 8 = 26 Now remove the OUTSIDE 3 electrons. We take away the 4s2 and 1 of the 3d to make [Ar] 3d^5 which is 18 + 5 = 23 and the Fe^+3 is 26-3=23.
*Monday, June 28, 2010 at 8:34pm by DrBob222*

**algebra**

3(d-8)-5=9(d+2)+1 Do the multiplication, then combine like terms: 3d - 24 - 5 = 9d + 18 + 1 -29 -18 -1 = 9d - 3d -48 = 6d -8 = d
*Wednesday, October 14, 2009 at 2:49pm by Ms. Sue*

**Chemistry**

Yes, it has 3 unpaired electrons BUT 4s2 are missing for the Co^+2 ion in the compound CoCl2.6H2O. You wrote the electron configuration for the neutral atom. Do you know how to almost without thinking write the 3d electrons in the 3d transition series. It's the DrBob rule.
*Tuesday, October 19, 2010 at 9:31pm by DrBob222*

**history**

I have to make do a 3d affect in a shoe box of a famous black peson. I came up with marion anderson singing at the white house. How or what can I do to make the 3d affect
*Sunday, January 23, 2011 at 6:40pm by nyia*

**Calculus Help Please!!!**

the normal line is perpendicular to the tangent line. Since the slope of the tangent line at x is y', find y'. 2x + 4y + 4xy' + 2yy' = 0 y' = -(2x+4y)/(4x+2y) = -(x+2y)/(2x+y) So, at (2,1) the tangent line has slope -4/5 Thus, the normal line has slope 5/4. Now you have a ...
*Tuesday, April 8, 2014 at 12:56pm by Steve*

**algebra**

3d+d=23 d=23/4=5.75 feet 3d= you do it.
*Monday, October 4, 2010 at 5:23pm by bobpursley*

**9th Chemistry**

I think you mean big spaces IN the 2nd and 3rd periods. There are no elements in columns #3 to #12 because there is no "2d" subshell of electrons. Also because the energy of the 3d subshsell is higher than that of the "4s" subshell. The first row of elements that contains "d" ...
*Sunday, November 8, 2009 at 8:54pm by GK*

**Chemistry**

The configuration of Mn, atomic number 25 is 1s2 2p2 2p6 3s2 3p6 3d5 4s2. Except for Cu and Cr, the 3d elements have the number of electrons in the 3d shell that is the same as the second number of the atomic number. Thus, Mn has 5 electrons in the 3d shell. And Hund's rule of...
*Monday, September 21, 2009 at 6:31pm by DrBob222*

**Algebra 2**

d^3 + 3d^2(-4b) + 3d(-4b)^2 + (-4b)^3 = d^3 - 12d^2b + 48db^2 - 64b^3
*Sunday, December 8, 2013 at 2:47pm by Steve*

**Math**

Okay, but I was stuck when trying to find the answer. My process was: n-6=(1/4)n n=(6^1/4)n at this step I am stuck to know what to do next. Please help.
*Thursday, January 9, 2014 at 4:03pm by Nicole*

**Little help with math?**

What does "put it to repeat" mean? http://www.google.com/search?q=48.03+%2F+7+%3D&aq=f&oq=48.03+%2F+7+%3D&aqs=chrome.0.57j0j62.1553&sourceid=chrome&ie=UTF-8
*Monday, March 25, 2013 at 5:55pm by Writeacher*

**chemistry**

We take from the 4s level first and go to the 3d to form the ions from the neutral atom. For example, Cu is 1s2 2s2 2p6 3s2 3p6 3d10 4s1. Remove the 4s electron to form Cu+ and remove the 4s1 and 1 of the 3d to make Cu^2+. Cr is 1s2 2s2 2p6 3s2 3p6 3d5 4s1 Remove 4s1 to form ...
*Tuesday, August 30, 2011 at 9:15pm by DrBob222*

**math**

4th term is 3 times 1st term ----> a+3d = 3a 2a = 3d a = 3d/2 7th term exceeds the 3rd term by 1 a+6d > a+2d by 1 a+6d = a+2d + 1 4d = 1 d = 1/4 then a= (3/2)(1/4) = 3/8 10th term = a+9d = 3/8 + 9(1/4) = 21/8 check: a=3/8, d=1/4 or 2/8 3/8, 5/8, 7/8, 9/8, 1/8, 13/8, 15/8...
*Thursday, December 8, 2011 at 8:13am by Reiny*

**Trigonometry**

http://www.wolframalpha.com/input/?i=plot+r+%3D+%3D+4%281-cos%28theta%2Bpi%2F4%29%29
*Tuesday, December 10, 2013 at 9:16am by Reiny*

**math**

make a list of ways to obtain 60¢ starting with the largest coins 2Q, 1D 2Q 2N 1Q 3D 1N 1Q 2D 3N 1Q 5N 6D 5D 2N 4D 4N 3D 6N 2D 8N 1D 10N
*Sunday, May 16, 2010 at 6:31pm by Reiny*

**science**

I have to do a report on a turtle and I need to do a display or 3d poster of some sort any ideas on how to make a 3d turtle or what I can use as supplies on how to make a turtle? And no live animals
*Thursday, December 4, 2008 at 4:59pm by Lexy*

**Maths**

1 a 2 a+d 3 a+2d 4 a+3d 5 a+4d n a + (n-1)d (a+2d)/(a+4d) = 3/7 3 a + 12d = 7a + 14 d 4a=-2d d = -2a fourth/sixth (a+3d)/(a+5d) = (a-6a)/(a-10a) = -5a/-9a = 5/9 etc
*Wednesday, January 22, 2014 at 6:08pm by Damon*

**Math**

Good Grief !! http://www.wolframalpha.com/input/?i=plot+y+%3D+ln%7CSin2X-CosX-1%7C+ First of all, if ln (something) = 0 then (something) = 1 so sin 2x - cosx - 1 = 1 or -1 easy one first: sin 2x - cosx - 1 = -1 2sinxcosx - cosx = 0 cosx(2sinx - 1) = 0 cosx=0 or sinx= 1/2 x...
*Monday, December 2, 2013 at 10:11pm by Reiny*

**mathes**

Let the point of contact be P(a,b) or P(a, √(a-3) ) If it is to be a normal at P, then the tangent at P must be perpendicular to 6x + 3y - 4 = 0 that is, the tangent must have a slope of +1/2 dy/dx = (1/2)(x-3)^(-1/2) = 1/( 2√(x-3) ) 1/(2√(x-3) ) = 1/2 2&#...
*Monday, December 16, 2013 at 1:07pm by Reiny*

**Calculus Help Please!!!**

f(x) is differentiable on the interval. So, you know there is a c such that f'(c) = (f(2)-f(0)/(2-0) = (-1-2)/2 = -3/2 So, just solve for c in 4c-5 = -3/2 c = 7/8 as a check, view http://www.wolframalpha.com/input/?i=plot+y+%3D+2x^2-5x%2B1+and+y+%3D+%28-3%2F2%29%28x-7%2F8%29...
*Tuesday, April 1, 2014 at 10:08pm by Steve*

**Calculus**

y = xe^(-4x) y' = (1-4x)e^(-4x) y" = 8(2x-1)e^(-4x) since e^(-4x) > 0 for all x, y" < 0 when 2x-1 < 0. see the graph at http://www.wolframalpha.com/input/?i=+xe^%28-4x%29+for+0+%3C%3D+x+%3C%3D+1
*Saturday, April 12, 2014 at 5:07pm by Steve*

**algebra**

4(3d-2)=3d-5
*Wednesday, October 17, 2012 at 8:31pm by itoria*

**Math**

P(x) =(2x+1)(x+3)(x-3)/((x-3)(x+2) = (2x+1)(x+3)/(x+2) When x = 3 , in new P(3) = 7(6)/5 = 42/5 so there is a hole at (3, 42/5) using P(x) = (2x+1)(x+3)/(x+2) = (2x^2 + 7x + 3)/(x+2) = 2x+3 - 3/(x+2) so we have an oblique asymptote y = 2x +3 see graph http://www.wolframalpha....
*Friday, November 29, 2013 at 8:17pm by Reiny*

**Calculus - Partial Fractions**

I've set a problem up, something like this. s^4: A+D=0 s^3: -2A+B-3D+E=0 s^2: 2A-B+C+3D-3E=0 s^1: -2A+B-D+3E=4 s^0: A+C-E=4
*Monday, March 24, 2008 at 10:02pm by David*

**arithmetic**

Assuming you are working with arithmetic sequences, term(4) = a+3d = 20 term(7) = a+6d = 32 subtract the two equations: 3d = 12 d = 4 sub back into either top equation to find a term(n) = a + (n-1)d
*Tuesday, October 13, 2009 at 7:08am by Reiny*

**Calculus**

You are right to have those two asymptotes. look at http://www.wolframalpha.com/input/?i=plot+y+%3D+%28x%5E2%2B4x-5%29%2F%28x-2%29+%2C+y+%3D+x%2B6 What happens at the far right and the far left ?
*Tuesday, April 8, 2014 at 10:44pm by Reiny*

**surface area & volume**

well, you do have a problem. Unless they give you the height of the prism, you're stuck. It's like asking for the area of a rectangle if they only give you the length. The prism is a 3D figure, and they have only given you the information on the base.
*Monday, November 12, 2012 at 10:01am by Steve*

**chem**

Indicate which is lower in energy in a many-electron atom: 3d or 4s Would it be 4s [because it fills before 3d]? That is correct is almost all cases. There is an exception for Cr and Cu; however, I think the intent of the problem clearly means the 4s (and for the reason you ...
*Tuesday, November 7, 2006 at 3:53pm by Alyssa*

**Trigonometry**

http://www.wolframalpha.com/input/?i=x+%3D+3+cos+θ+and+y+%3D+3+sin+θ+for+0≤θ≤π
*Saturday, November 30, 2013 at 11:59am by Reiny*

**Chemistry: Electron Configurations**

23V = 1s2 2s2 2p6 3s2 3p6 3d3 4s2 = 23 electrons. Then you remove the last 3 electrons (an this is where you probably made your error). The last three electrons are the 2 4s electrons and 1 of the 3d so the final configuration will be 1s2 2s2 2p6 3s2 3p6 3d2 = 20 electrons. ...
*Wednesday, November 4, 2009 at 10:27pm by DrBob222*

**physics**

It is the hor. component of force that moves the roller: Fh = 127*cos(22.5) = 117.3N. P = FD / t = 64.3W, 117.3D / 90 = 64.3, 1.3D = 64.3, D = 64.3 / 1.3 = 49.5m.
*Monday, January 17, 2011 at 10:18am by Henry*

**Calculus Help Please!!!**

just follow the theorem. f(0) = 1 f(2) = -1 so, the average slope on the interval is (-1-1)/(2-0) = -1 So, now we need to find c such that f'(c) = -1 f'(x) = 4x-5 so, where does 4x-5 = -1? x = 1 1 is inside [0,2], as predicted by the Theorem. In fact, since f(1) = -2, the line...
*Friday, April 4, 2014 at 11:12pm by Steve*

**Calculus**

Here is a sketch http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E2+−+4x+%2B+1+and+y+%3D+−x%5E2+%2B+4x+−+5 Easy to find their intersection points: (1, -2) and (3, -2) effective height between x = 1 and x = 3 = (-x^2 + 4x - 5) - (x^2 - 4x + 1) = -2x^2 +8x -...
*Wednesday, December 11, 2013 at 6:34pm by Reiny*

**Math again**

Rearrange to give d in terms of e: (3d-7)/(4+5d) = e I got 3d - 5de = 4e + 7 but where do I go from there? Thanks :) 1st you must Multiply the polynomial. Please try the tutorial at the following site: http://www.webmath.com/polymult.html
*Monday, May 28, 2007 at 2:05pm by Emma*

**Chemistry**

Which of the following electron configurations of neutral atoms represent excited states? [Xe]6s^2 4f^1 [Ar]4s^2 3d^3 1s^2 2s^2 2p^6 3s^2 3p^6 3d^2 [Kr]5s^1 4d^5 2s^2 Which neutral atoms have the following electron configurations? Enter the name or symbol. [Ar]4s^2 3d^3 [Kr]5s...
*Sunday, March 24, 2013 at 11:59pm by Anonymous*

**history**

Here are some links on 3D boxes to try: http://search.yahoo.com/search?fr=mcafee&p=how+to+make+a+3D+affect+in+a+shoe+box You picked a marvelous person! Good luck! Sra
*Sunday, January 23, 2011 at 6:40pm by SraJMcGin*

**Calculus Help Please!!!**

only valid for 90 ≤ x ≤ 1 http://www.wolframalpha.com/input/?i=y+%3D+%3D+8x%28√%28x+−+x%5E2%29%29+%2C+0+%3C+x+%3C+1
*Friday, April 4, 2014 at 9:16pm by Reiny*

**Chemistry**

The following electron configurations correspond to the ground states of certain elements. Name each element. a) [Ar]3d^10 4s^2 4p^4 b) [Ne]3s^2 3p^3 c) [Ar]3d^2 4s^2 d) [Kr]4d^1 5s^2 e) [Xe]4f^13 6s^2
*Monday, November 26, 2012 at 12:33pm by Chironjit*

**chemistry**

The easy way to know the electronic structure for the 3d elements is to follow DrBob's rule. The number of electrons in the 3d orbtials for the 3d transition metals is the second number of the atomic number (EXCEPT for Cr and Cu). For Co, atomic number 27, that means we have 7...
*Sunday, July 11, 2010 at 2:01pm by DrBob222*

**Chem 1C**

[Ar]3d^8 and [Ar]3d^5
*Wednesday, June 30, 2010 at 2:25am by Anonymous*

**Chem 1C**

[Ar]3d^8 and [Ar]3d^5
*Wednesday, June 30, 2010 at 2:25am by Anonymous*

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