Friday

December 9, 2016
Total # Posts: 47,035

**Order MATH!**

2/3 = 0.66 7/10 = 0.70 now things should be clear.

*November 18, 2016*

**maths**

the area is just 1/2 ab the area is just 1/2 bc sin?

*November 18, 2016*

**maths**

(a) ? is easy, since the angles sum to 180° Then use law of sines to find b,c (b) this is a right triangle. a^2 = b^2+c^2 then just use the trig functions to get the other two angles. (c) use the law of cosines to get any or all of the angles. Or, having one, you can use ...

*November 18, 2016*

**maths**

find the reference angle in QI. only sin x is positive in QII. For example, cos x = ?2/2 x = 45° Since cos x < 0 in QII, that is the only solution. Work the others in like wise.

*November 18, 2016*

**Maths**

just list the terms. 6 is the last to appear.

*November 18, 2016*

**Maths**

Think of a rectangle. The maximal area is achieved when it is a square. Similarly for a rectangular prism, the maximum volume is when it is a cube. so, in this case, the sum is just 3?2001

*November 18, 2016*

**Geometry**

#4 Remember the 3-4-5 right triangle. This is just double that. You got #1 right. How could you not be sure on #4?

*November 18, 2016*

**Geometry**

#1 ok #2 the sides are 26/?2 = 13?2 If the sides of a square are 1, the diagonal is not 2. #2 In such a triangle, the sides are 1,?3,2 Now multiply everything by 8. (c) is wrong.

*November 18, 2016*

**math**

and how did you arrive at that figure? Take a piece of graph paper and draw a 6x8 rectangle on it. You really think the diagonal is 48? Think of the Pythagorean Theorem here.

*November 18, 2016*

**Math**

she got 1/6 wrong. so, ...

*November 18, 2016*

**Calc**

I assume you mean x^(2/5) since f' = 2/5 x^(-3/5) it is undefined at x=0

*November 17, 2016*

**Calculus**

are they the same?

*November 17, 2016*

**Calculus**

a = ?(x/2?)^2 + (14-x)/6 * (14-x)/3 P = (12+x)(27-3x) - (4x)

*November 17, 2016*

**calculus**

11,33,55,77,99,121,319,517,539,...,979

*November 17, 2016*

**Math**

see related questions below

*November 17, 2016*

**mathematics**

no idea. Where is D?

*November 17, 2016*

**Math algebra**

(20+2w)(30+2w) = 936 w = 3

*November 17, 2016*

**Algebra**

you want x^2+y^2+6y+5 = x^2+y^2-2x-8 6y+5 = -2x-8 y = -(2x+13)/6 Now use that to find x: x^2 + (-(2x+13)/6)^2 - 2x - 8 = 0 40x^2 - 20x - 119 = 0 x = [5±9?15]/20 y = -3/20 (15±?15) http://www.wolframalpha.com/input/?i=solve+x%5E2%2By%5E2%2B6y%2B5%3D0,+x%5E2%2By%...

*November 17, 2016*

**math**

a = bh/2 so, 5b/2 = 15

*November 17, 2016*

**Linear Programming - The Graphical Method**

This web site is very useful: http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html

*November 17, 2016*

**Math (equation of tangent line)**

2xy-1=(x+y+1)^2 2y + 2xy' = 2(x+y+1)(1+y') 2y + 2xy' = 2(x+y+1) + 2(x+y+1)y' y' (2x - 2(x+y+1)) = 2x+2 y' = -(x+1)/(y+1) So, your derivative is ok. when y = -1, x = -1, so y' = 0/0 so, what happens near (-1,-1)? If y = -1+h, x = -1+h+?(2h) so, y'...

*November 17, 2016*

**Pre-Calc**

sin(kx) has period 2?/k tan(kx) has period ?/k so, crank it out.

*November 17, 2016*

**ELITRICAL MATH! (LAST ONE FOR TODAY, HOPEFULLY!)**

divide cost/quantity $1.49/3ft = $0.4967/ft and similarly for the other one. Then compare

*November 17, 2016*

**Math**

8^-2 = 1/8^2 = 1/64 4^-2 * 2^0 = 1/16 * 1 = 1/16 5^(2-1+3) = 5^4 Your typos make things hard to read

*November 17, 2016*

**Math**

yes.

*November 17, 2016*

**Math**

just substitute: y = x-2, so x^2 - x(x-2) + 3(x-2)^2 = 15 3x^2 - 10x - 3 = 0 solve for x, than y=x-2.

*November 17, 2016*

**Math**

6 * 1/3 = 2

*November 17, 2016*

**Algebra**

You have two circles: x^2 + (y+3)^2 = 6 (x - 9/2)^2 + y^2 = 105/4 Naturally, they intersect where x^2+y^2+6y+3 = x^2+y^2-9x-6 6y = -9x-9 y = -(3x+3)/2 Subbing that into one of the equations, x^2+(3x+3)^2/4-9x-6=0 13x^2 - 18x - 15 = 0 x = 1/13 (9±2?69) y = -3/13 (11&...

*November 17, 2016*

**Math**

well, g = f-7 so what do you think?

*November 17, 2016*

**Math**

The only reason I can think of is that a measurement is subject to error (and is really only a decimal approximation), whereas the PT results is exact.

*November 17, 2016*

**Differential Calculus**

I do not know what cos^y means. I'll just use cosy and you can fix it as needed. x^2 cosy - siny = 0 2x cosy - x^2 siny y' - cosy y' = 0 y' = (2x cosy)/(x^2 siny + cosy) so, at (0,?), y' = 0 Since the tangent is horontal, the normal is vertical, and the ...

*November 17, 2016*

**maths**

40 = 360/9 so, 1/9 of the whole area.

*November 17, 2016*

**maths**

35 min = 7/12 of an hour. That is, 7/12 of the circumference of a circle with radius 6 cm. so, ...

*November 17, 2016*

**Algebra**

correct

*November 17, 2016*

**Math**

add up the total points so far. He needs 4*59 so, how many points short is he?

*November 17, 2016*

**Maths**

Check with "Ed" below ...

*November 17, 2016*

**Maths**

h = 1 + 3t - 4.9t^2 You forgot about gravity

*November 17, 2016*

**Maths**

h - 4.9 * 1.5^2 = 0 v = -9.8t

*November 17, 2016*

**Math**

try here: http://davidmlane.com/hyperstat/z_table.html

*November 17, 2016*

**Geometry**

also, 19x-11 = 10x+7

*November 17, 2016*

**maths**

ok, now what?

*November 17, 2016*

**math**

by, not bye 29+16/9 = 30 7/9 I assume you meant (28+16)/9 = 45/9 = 5 Online, parentheses make a big difference!

*November 17, 2016*

**math**

Looks like a good unit to study, all right. Do you have any specific questions that are causing you difficulties? Do not expect someone here to provide you with all the answers...

*November 17, 2016*

**Scale Math HELP!!!!!!!!!!**

1.29 * 6.5 * (how many sides?)

*November 17, 2016*

**Fizik**

All your numbers are missing, but just find the net force and then use F = ma v = at s = 1/2 at^2

*November 17, 2016*

**Tod**

input your data here for the solution, as well as a graph of the region: http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html

*November 17, 2016*

**Math grade 6, four operations**

a+b+c = 75 a-28+19 = b+28-24 = c+24-19 or a+b+c = 75 a-9 = b+4 a-9 = c+5

*November 17, 2016*

**math**

the image is the same distance above the line y = -2 as it was below it to start. So, y -> -2+(-2-y) = -2+(y+4) = y+2 (-1,-3) -> (-1,-1)

*November 17, 2016*

**math**

14/16 = 7/8 = 35/40 1/5 = 8/40 now just add them up

*November 17, 2016*

**Maths**

500,000 + .05*1000,000 + .125*(1,200,000x-1,000,000) = 1,400,000 Too many zeros! Let's knock of 000,000 and we have (in millions) 0.5 + .05*1 + .125(1.2x-1) = 1.4 Better check my numbers. I get x = 6.5 ...

*November 17, 2016*

**math**

since the numerators are all the same, larger denominators means smaller numbers.

*November 17, 2016*

**Integral Calculus**

Looks to me like an = (-1)^(n-1) (n+1)!/4^(n-1)

*November 17, 2016*

**math**

5(a+4d) = 12(a+11d) 5a+20d = 12a+132d 7a = -112d a = -16d so, what is the 17th term?

*November 17, 2016*

**Math (Slope of inverse tangent line)**

correct

*November 17, 2016*

**Morales**

black: x(x+8) green: (x+3)(x+8) (x+3)(x+8) = x(x+8)+39

*November 16, 2016*

**mathematics**

8m+4n=12 3m+4n=2 subtract to get 5m = 10 ...

*November 16, 2016*

**Math**

I assume you meant interior diagonal x^2+2x+1 = (x+1)^2 So, each edge of the cube has length (x+1). For a cube of side length s, the main diagonal has length s?3, since the diagonal on a face is s?2. the main diagonal is ?(2s^2+1) = s?3 So, for this cube, the main diagonal has...

*November 16, 2016*

**Algebra**

5918*1.026^t = 11000000

*November 16, 2016*

**Math**

of course it exists. It's just the difference of two polynomials, so it's another polynomial. (f-g)(3) = f(3)-g(3) Now just plug in their values and simplify.

*November 16, 2016*

**Algebra**

since the roots come in conjugate pairs, y = (x+?3)(x-?3)(x-4i)(x+4i) = (x^2-3)(x^2+16) ...

*November 16, 2016*

**Differential calculus**

see related questions below.

*November 16, 2016*

**Algebra**

not even close. See other post(s) on this problem.

*November 16, 2016*

**Math**

3a-4 = 5 3a < 9 a < 3 And that's "explain" not "expiation," which is something else entirely! (and not even a verb)

*November 16, 2016*

**Math**

(n)/(-3)+5>4 (n)/(-3)+1 > 0 1 > -n/(-3) 1 > n/3 3 > n or, n < 3

*November 16, 2016*

**Physics**

no, it is just the 3 meter part that is submerged. If it sinks, then the displaced water has the same volume as the object.

*November 16, 2016*

**Math**

must be polar bears.

*November 16, 2016*

**math**

each gets 1/4 of the candy! But I think you are asking how much of the original candy bar each person gets. That would of course be 1/4 * 2/3 Make sure you ask what it is you want to know.

*November 16, 2016*

**math**

in an equilateral triangle, the altitudes are the medians. So, the radius of the circle is 2/3 of the length of each altitude. ...

*November 16, 2016*

**math**

As I said earlier, http://www.jiskha.com/display.cgi?id=1479327393

*November 16, 2016*

**math**

You are correct. I calculated using 2/3 of the projection of the median, which is wrong. I'll think on it some more. You do the same...

*November 16, 2016*

**math**

since the centroid is 2/3 of the way from each vertex to the opposite side, the projections on the sides are 2/3 the length of the sides. Their sum is thus 2/3 of the perimeter of ABC = 8

*November 16, 2016*

**math**

CDE is a 30-60-90 right triangle with ?C=30, so DE = 15.

*November 16, 2016*

**math**

better this time. B is correct

*November 16, 2016*

**Algebra**

If you went from 9|9-8x|=2x+3 to 8x=2x-6 you certainly did not divide by 9 (on BOTH sides)! All absolute-value problems have two possibilities. First, 9(9-8x)=2x+3 81-72x = 2x+3 78 = 74x x = 39/37 Second, 9(9-8x) = -(2x+3) 81-72x = -2x-3 70x = 84 x = 6/5

*November 16, 2016*

**Algebra**

|-4(-2)-8| + |-1-(-2)^2| + 2(-2)^3 |-4(-2)-8| + |-1-4| + 2(-8) |8-8| + |-1-4| - 16 0+5-16 -11

*November 16, 2016*

**Math**

no. 5:9 = ratio of squares:total squares:circles = 5:4

*November 16, 2016*

**Math - OK**

Huh. CDAC is correct. Don't know why I said otherwise. My bad. Sorry.

*November 16, 2016*

**Math**

NO stop guessing and do the math! I even gave you the numbers!

*November 16, 2016*

**Math**

#1 15/50 = 3/10 #2 D is correct #3 70/200 = 35/100 #4 820 * .04 * 3 = ? Looks like you need some review.

*November 16, 2016*

**Calculus**

You should know immediately that 27/4 is not correct, since it does not lie in the interval [0,3]! You want c such that f'(c) = (f(3)-f(0))/(3-0) 3c^2 = 27/3 c = ?3

*November 16, 2016*

**Math**

2(x+12) = 3/2 (2x+12)

*November 16, 2016*

**algebra 1**

16/6

*November 16, 2016*

**math**

44 is the answer, so I suspect a typo. k = 8*110/20 = 44

*November 16, 2016*

**math**

well, 25=5^2 and 9=3^2, so try (5x+3)^2 = ? Note that you will get two answers.

*November 16, 2016*

**MATH**

Odd. It agrees with the formula here http://www.had2know.com/academics/paraboloid-surface-area-volume-calculator.html Better double-check my numbers.

*November 16, 2016*

**MATH**

In cylindrical coordinates, you have z = r^2 r = 2 symmetry allows us to say v = 4?[0,2]?[0,?/2] r^2 * r dr d? = 4?[0,2]?[0,?/2] r^3 dr d? = 2? ?[0,2] r^3 dr = 2? * 16/4 = 8?

*November 16, 2016*

**math**

k = 8*110/20 = 44 I suspect a typo somewhere.

*November 16, 2016*

**Calc**

I think it is true.

*November 16, 2016*

**Algebra**

It is the same as saying that a 0 is picked, either as 1st or 2nd pick: (1/6)(1) + (5/6)(1/5) = 1/3

*November 16, 2016*

**Algebra**

(3x/5-7)+7 Just get rid of the parentheses: 3x/5 - 7 + 7 3x/5

*November 16, 2016*

**math**

(5x+3)^2 = ?

*November 16, 2016*

**Math**

or, to work with smaller numbers, divide by 7 and then multiply by 22.

*November 16, 2016*

**math**

since time = distance/speed, 30/a = 30/b + 2 30/(2a) = 30/b - 1

*November 16, 2016*

**Algebra**

If you add the two equations, you get 12x = 24 because -8y+8y = 0 Now you know x=2, so y=0

*November 16, 2016*

**Algebra**

rewrite #1 and you get 10x-8y=20 2x+8y=4 Now add the two equations and y goes away. Solve for x, then get y.

*November 16, 2016*

**Fibonacci Sequence - malformed**

I assume you mean Un+1 = 3Un + 1/(5Un+3) since no other interpretation makes any sense. But that's not an integer sequence. So, how about fixing your typos, using parentheses, and maybe say U<n+1> to avoid mixing subscripts with numeric values?

*November 16, 2016*

**FLAGPOLE MATH!**

the ratio of shadow_length to height is the same for pole and girl, so s/12 = 4/5

*November 16, 2016*