Tuesday

September 30, 2014

September 30, 2014

Total # Posts: 25,365

**Math (Exponents)**

Do you mean 4*10^0 + 7*10^-1 + 2*10^-2 + 8*10^-3? If not, maybe you could splain just what you do want.
*September 18, 2014*

**Math-The chain rule HELP**

y = 1/u dy/dx = dy/du * du/dx = -1/u^2 * 6x = -6x/u^2 = -6x/(3x^2+5)^2
*September 18, 2014*

**math**

I'd start with the biggest book: 200 = 100+100 200 = 100+50+50 200 = 100+50+10+10+10+10+10 and so on, breaking each possible book down into its parts. Watch out for duplicate entries.
*September 18, 2014*

**trig**

Review your basic trig functions. As always, draw a diagram. If the distance is x, tan65° = x/30
*September 18, 2014*

**Algebra2**

Since the peak height of 15 was reached at t=3, h(t) = a(t-3)^2 + 15 Since h(0) = 7, a = -8/9, so h(t) = -8/9 (t-3)^2 + 15 Now you can answer the questions
*September 18, 2014*

**Math**

Surely you can determine T1 ?? Clearly d = -2b So now just apply your formulas.
*September 18, 2014*

**Math**

no diagrams here, but a google on vectors dot product will turn up many discussions and diagrams.
*September 18, 2014*

**Math**

t1 = 7/4 d = -3/4 Tn = 7/4 - 3/4 (n-1) ...
*September 18, 2014*

**Math**

T2-T1 = 1/20 T3-T2 = 1/12 So, not arithmetic T2/T1 = 5/4 T3/T2 = 4/3 So, not geometric
*September 18, 2014*

**Math**

I suspect a typo. Moving right along, S8 = a(1-r^8)/(1-r), so just plug in your values.
*September 18, 2014*

**math**

It would certainly be easier to analyze the situations if you had not run them all together into one long sentence. Take the last one. Clearly the net charge is 12(0 + 1 + (-1)) = 12(0) = 0 Surely you have some thoughts on the others. Don't get rattled by all the words; ...
*September 18, 2014*

**Math**

Clearly, the nth winner gets 250000 * 0.20^(n-1) This is just a geometric series with a = 250000 r = 1/5 So, just apply your seies formulas
*September 18, 2014*

**Algebra**

Assuming a shift to the right, that would be g(x) = (x-2)^2/5 See http://www.wolframalpha.com/input/?i=plot+y+%3Dx^2%2C+y%3D%28x-2%29^2%2F5+for+-3%3C%3Dx%3C%3D5
*September 18, 2014*

**math**

I suspect the t was supposed to be a y, making things 3p(x-y) - (x-y) (3p-1)(x-y)
*September 18, 2014*

**algebra**

well, that would clearly be 36 + 43e^(-0.058*14)
*September 18, 2014*

**math**

That means the exterior angles are 40, so there are 9 sides.
*September 18, 2014*

**Math algebra**

probably OOUUUUCCCHHH!!
*September 18, 2014*

**sixth grade math**

Odd - you got #1 correct, but missed the other two. 1 5/6 * 2/3 = 11/6 * 2/3 = 22/18 = 11/9 7/8 * 3 1/3 = 7/8 * 10/3 = 70/24 = 35/12 How ever did you arrive at those answers? #2 I could call a typo, but not #3.
*September 17, 2014*

**Chem**

wow - can't believe I mangled those digits! But you noticed that on your own, right, Jessica? :-)
*September 17, 2014*

**Chem**

the density is evidently 29.3g/(16.7-14.2)ml = 23.9/2.5 = 9.56 g/cm^3 Find that in your table of materials
*September 17, 2014*

**Math**

90 boys like soccer, so 150 boys like basketball Assuming those were the only two sports in the survey, that means 240 boys were surveyed. So, 240 girls were surveyed. That means 210 liked soccer and 30 liked basketball.
*September 17, 2014*

**math**

Who knows what the names are? But, doing the algebra, 2x^2+3x+1 + x^2+5x+8 = 3x^2+8x+9
*September 17, 2014*

**Math**

The LCM is the product if they have no factors in common (relatively prime) Now it should be easy to pick the proper pairs. In fact, since they actually gave you the LCM's, it's just a matter of seeing whether the two numbers multiply to give the indicated LCM!
*September 17, 2014*

**Algebra**

Assumiong all the tiles are to be used, find the GCF(45,75,90). That is 15 45 = 3*15 75 = 5*15 90 = 6*15 So, he can make 15 stones, each with 3 red, 5 yellow a
*September 17, 2014*

**science/math**

How ever did you get a negative number? I'd assume we are using the same positive acceleration, starting from 50 mph! assuming constant acceleration, then since the velocity changed by 88ft/s in 8 seconds, a = 11 ft/s^2 Now to find v, just recall that v(t) = Vo + at Just ...
*September 17, 2014*

**Algebra! please help**

first, complete the squares: x^2+x + y^2-6y = -9 x^2+x+(1/4) + y^2-6y+9 = -9 + 1/4 + 9 (x + 1/2)^2 + (y-3)^2 = 1/4 Now all should be clear. See http://www.wolframalpha.com/input/?i=x^2%2By^2%2Bx-6y%2B9%3D0
*September 17, 2014*

**business in mathematics**

After 10 5/12 years, the amount is 9500(1 + .055/4)^(4*10.417) Not sure how the periods are divided into pieces.
*September 17, 2014*

**Algebra 1**

what are the numbers moving away from 0? Surely you can figure out how many stairs she has to climb. She has to go down 4, back up to 0, and then up another 4, then back to 0.
*September 17, 2014*

**Algebra**

3(a-2) = a 3a-6 = a 2a = 6 a = 3
*September 17, 2014*

**Physics Grade 12**

solve for t when the distances are equal: 0 + 1.1t^2 = 12.2t Now recall that since she started from a dead stop, s = 1/2 at^2 v = at
*September 17, 2014*

**Algebra**

Assuming the ) means a 0, we want 125 + 0.15x = 75 + 0.40x
*September 17, 2014*

**math**

If the rate is constant, then t = md+b Now plug in two pairs of values, say the first two. 8 = 40a + b 6 = 56a + b So, a = -1/8 and b=13 t = -1/8 d + 13 Now check the other two pairs of values to make sure they agree.
*September 17, 2014*

**math help ASAP!!**

Do you mean you want to solve the equation? (3x-2)/(x+4) = (18-4x)/(x^2-16) - (3x+2)/(4-x) You need a common denominator. Since x^2-16 = (x-2)(x+2), then assuming x ≠ ±4, (3x-2)(x-4) = (18-4x) + (3x+2)(x+4) Now you can rearrange terms to get -6(4x+3) = 0 so, x = -3/4
*September 17, 2014*

**algebra**

I assume you want to find the roots of the function. Since there are no rational roots, wolframalpha is your friend: http://www.wolframalpha.com/input/?i=x^3-9x%2B1
*September 17, 2014*

**Math**

x=0, or 7x = 8 If you rearrange terms, 7x^2 - 8x = 0 x(7x-8) = 0
*September 17, 2014*

**Math**

You have a slope and a point, so y-3 = -1/3 (x-1) Now all should be clear.
*September 17, 2014*

**Math:Algebra 2**

geez, give it a rest, ok?
*September 17, 2014*

**algebra 2**

If you are in algebra 2, I guarantee that you were taught this. Remember the point-slope form for a line? It's in your text.
*September 17, 2014*

**M**

You have a point and a slope, so use the point-slope form for a a line: y-3 = -2(x-1)
*September 17, 2014*

**math**

1/8 the circumference is pi. So, the whole circumference is 8pi Since C = pi*d, d = 8
*September 17, 2014*

**math**

John has to make up 50 miles at 10 mi/hr That will take 5 hours.
*September 17, 2014*

**6th grade math**

Since a and b are both positive, as long as a < b, a/b < 1 if a > b, a/b > 1 So, just pick some values for each case.
*September 17, 2014*

**math**

3/8 ÷ 0.5 = 3/4 2.5 ÷ 18/8 = 2/5 Since 3/4 > 2/5, he has too much milk. He'll get runny pancakes.
*September 17, 2014*

**science/math**

assuming constant acceleration, then since the velocity changed by 88ft/s in 8 seconds, a = 11 ft/s^2 Now to find v, just recall that v(t) = Vo + at Just plug in your numbers. Of course, in the real world, acceleration from a standing start is very different from a starting ...
*September 17, 2014*

**math**

Since it is a parabola which opens upward, there is no maximum value. g(x) = 2(x + 3/2)^2 - 3/2 so its minimum is -3/2
*September 17, 2014*

**Math**

4 -5 7
*September 17, 2014*

**Music**

ever heard of google? You will get much more info than you can use in a short paper.
*September 17, 2014*

**Physical Science**

since density = mass/volume, volume = mass/density. So, you will displace 3800g / (19 g/cm^3) = 200 cm^3
*September 17, 2014*

**java**

you can do one of two things. (1) use a pattern match to place the digits into an array, then print the array elements. (2) convert the number to a string, then loop through the string, printing the 1st character and then removing it, till the string is empty.
*September 17, 2014*

**java**

so, the next step will be to accept use input. Check how to do that.
*September 17, 2014*

**Create math equation**

If we place Kingston at (0,0) and Queensville at (0,160), then a time t from when Anthony left, the positions will be equal: 45t = 160-40(t - 1/4) t = 2 So, they meet at 2:00+2 = 4:00 pm Or, consider it like this. In the first 15 minutes, Anthony went 45/4 miles. The two cars ...
*September 17, 2014*

**physics**

the velocity changes by -20.8 m/s in 3.58s, for an acceleration of (-20.8 m/s) / 3.58s = -5.8 m/s^2
*September 17, 2014*

**algebra**

presumably it evaporated or was ionized by the electricity and escaped as H2 and O2 molecules.
*September 17, 2014*

**math**

If the breadth is w and the length is x, then we have 2(w+x) = 38 x-3 = 2(w-3) Now just solve for w and x. The area is w*x.
*September 17, 2014*

**algebra**

Ix x ml of 10%, then the rest (600-x) is 4%. So, .10(x) + .04(600-x) = .06(600)
*September 17, 2014*

**Math**

a = 0.7 a+ar = 2.1 so, 0.7(1+r) = 2.1 1+r = 3 r = 2 So, now you know that S12 = a(1-r^12)/(1-r) Just plug in your values.
*September 17, 2014*

**Math**

a + a+d = 15 a+2d + a+3d = 43 collect terms to get 2a+d = 15 2a+5d = 43 That should get you started.
*September 17, 2014*

**math**

Enter your polynomials at calc101.com. Click on the long division button.
*September 17, 2014*

**Math (putting the question back up, again)**

-5/8 c = 20 c = 20(-8/5) = -32
*September 17, 2014*

**Math**

since a = 15 r = 1/3 S4 = a(1-r^4)/(1-r) = 200/9 as you can easily verify with any calculator
*September 17, 2014*

**Math**

The first 3 terms form a geometric sequence, but the last is way off scale. As for the sum, why don't you just add up the terms you have been given?
*September 17, 2014*

**Math**

t1 = 250000 r = 0.20 Now just plug those into the various formulas you have learned.
*September 17, 2014*

**Algebra help**

the slope of L is 3 so, the slope of all perpendiculars to L is -1/3 So, now you have a point and a slope. If that doesn't tell you which form of the equation to use, there's trouble in River City.
*September 17, 2014*

**math**

since x = r cosθ r = x/cosθ
*September 17, 2014*

**geometry**

No idea. Where is P?
*September 17, 2014*

**Math**

Nope. Forgot the 60 degree angle. In that case, recall that cos 60 = 1/2
*September 17, 2014*

**Math**

Hint: Think of the ubiquitous 3-4-5 right triangle, scaled up to 6-8-10.
*September 17, 2014*

**n2maths**

50^2 + x^2 = (x+10)^2
*September 17, 2014*

**Math**

It appears that the two boys are less than 10, since adding up all the ages gives only 83 Granny cannot be less than 83-17=66 66+8+9=83 67+7+9=83 68+6+9=68+7+8=83 69+5+9=69+6+8=83 71+5+7=83 72+4+7=72+3+8=72+2+9=83 73+3+7=83 WE HAVE A WINNER!
*September 17, 2014*

**maths**

having what as 5000m?
*September 17, 2014*

**Algebra**

correct both times. In general, for a given set of problems, U is the Universe. Any subsets being discussed will always be subsets of U, or things are poorly set up.
*September 17, 2014*

**Algebra**

so, use one. wolframalpha.com does a good job
*September 17, 2014*

**math**

We have two lines, with slopes (-5-b)/10 and (-3)/(-6-a) If the lines are perpendicular, then (-5-b)/10 * (-3)/(-6-a) = -1 (b+5) = 10/3 (a+6) b = 5/3 (2a+9)
*September 17, 2014*

**Math**

We have a=7 d=12 So, when does Tn exceed 1000? Tn = 7+12(n-1) = 12n-5 12n-5 < 1000 12n < 1005 n < 83.75 So, the first 83 terms are less than 1000 Similarly for 2000
*September 16, 2014*

**Math**

clearly, a = 28 r = 1/6 So, S = a/(1-r) = 28/(5/6) = 33.6
*September 16, 2014*

**Math**

since x has an unspecified value, there is no way to round it. So, I assume you want to solve the equation, and round the answer to two decimals. 2x^4+3x-4 = 0 There are only two real roots, x = -1.43 or 0.90 The graph is at http://www.wolframalpha.com/input/?i=2x^4%2B3x-4 Or...
*September 16, 2014*

**math**

16/10 is the same as 1.6
*September 16, 2014*

**math**

probably because you have learned by heart some simple results, like sums totaling 10, or 5, etc. The mechanics never change, so if some are easier, it just means that you have learned some patterns that you can recognize.
*September 16, 2014*

**math**

The language is very confusing in its use of present and past tenses. When is "now"? The end of the year? If girls joined the band, how come there are now fewer students than at the beginning? I cannot believe the question was posed as you state. If so, the problem ...
*September 16, 2014*

**trigo**

First, vessels travel on headings, not bearings. 200 @ 245° = (-181.262,-84.524) 50 @ 320° = (-32.134,38.302) add them up to get (-213.396,-46.222) = 218 @ 258°
*September 16, 2014*

**Algebra**

correct.
*September 16, 2014*

**Calculus**

f(a) = 3a^2-2a f(a+h) = 3(a+h)^2 - 2(a+h) = 3a^2 + 6ah + 3h^2 - 2a - 2h f(a+h)-f(a) = 6ah + 3h^2 + 2h So, (f(a+h)-f(a))/h = 6a + 3h + 2 So, with various values of h, f(a+1) = 6a+3+2 f(a+0.1) = 6a + 0.3 + 2 = 6a + 2.03 and so on. Nothing difficult, just algebra I.
*September 16, 2014*

**Math**

That's a lot of work. Just think about it a bit. You start with 1 gram. 3 days later the amount left is 0.1 gram If the half life is k days, then (1/2)^3k = 1/10 3k = log(.1)/log(.5) = 3.32 So, k = 1.11 R(t) = (1/2)^(1.11t) But, since we like things base e for our ...
*September 16, 2014*

**Math**

just solve for x in the equation −0.01x2 + 130x − 180,000 = 174900
*September 16, 2014*

**math**

The expression factors as (3x-1)(x+2) However, there are lots of other ways to divide things up. For example, if x=3, the area is 8*5 = 40, but those are not the only two ways to get two numbers which multiply to 40.
*September 16, 2014*

**math help**

Just plug in the value: (4x+8)(x+2)(2x+4) / 2((4x+8)(x+2)+(4x+8)(2x+4)+(x+2)(2x+4)) = 8(x+2)^3 / 28(x+2)^2 = 2(x+2)/7
*September 16, 2014*

**Math**

steps to what?
*September 16, 2014*

**math**

The answer is r^2-5 + 5/(r^2-2) See the details when you enter your polynomials at calc101.com. Click on the long division button.
*September 16, 2014*

**Math**

after n hours, the length is 3*3^(n-1) = 3^n Now just plug in n=3
*September 16, 2014*

**math**

since the circumference is 8*3.14, the diameter is 8
*September 16, 2014*

**math**

f = m+5 f+5 = 2m m+5 + 5 = 2m m = 5
*September 16, 2014*

**math**

the first car went 20 miles before the 2nd car started out. So, it made up 20mi/(5/3 hr) = 12 mi/hr That is, car 2 was going 12 mi/hr faster than car 1, or 72 mi/hr Check: car 1 went 120 miles in 2 hours car 2 went 72(5/3) = 120 miles in 1 hr 40 min
*September 16, 2014*

**Algebra**

g(f(x)) = {g(8),g(5),g(-5),g(3)} = {10,9,3} g(3) is undefined
*September 16, 2014*

**Algebra 2**

y = 2x-1 + 3/5
*September 16, 2014*

**Algebra 1**

your solution is correct. To check on (180,-30), plug it in 8(180)+5(-30) =?= 900 But, how do you sell -30 student tickets?
*September 16, 2014*

**Math**

(a) max height occurs at t = -87/-32 (b) just solve for t when h=0
*September 16, 2014*

**Trig**

if the wind speed is w and the plane's speed is s, then (w cos-135°,w sin-135°)+(s cos63°, s sin63°) = (550 cos64°,550 sin64°) -.707w + .454s = 241.104 -.707w + .891s = 494.337 w = 31.089
*September 16, 2014*

**c**

or, 1/4 + 1/(x+9) = 1/x x = 3 so, the 2nd hose takes 12 hours check: in 1 hour, the two hoses fill 1/4 + 1/12 = 1/3 of the pool.
*September 16, 2014*

**college algebra**

If you mean the increase occurs only for those in excess of 3000, then you have (20)(3000) + (20+0.01)(x-3000) = 153525
*September 16, 2014*

**Coordinate Algebra**

In point-slope form, we have y-4 = -3(x-5)
*September 16, 2014*

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