Saturday

October 25, 2014

October 25, 2014

Total # Posts: 26,094

**Physics**

yes. Friction is just another force; nothing special about it.
*October 6, 2014*

**College Physics**

a = (-284.4 m/s)/1.4s = -203.1 m/s^2 s = Vo t + 1/2 at^2 = 284.4*1.4 - 1/2 (203.1)(1.4^2) = 199.1 m
*October 6, 2014*

**Math**

If each member makes x candles, then 40x = 39(x+3) x = 117 So now you can find the total.
*October 6, 2014*

**MATH**

d/dx (x^5 + y^8) is indeed 5x^4 + 8y^7 y' Usually this is done in conjunction with implicit derivatives, where you have some equation like x^5 + y^8 = 7 and you wind up with y' = -5x^4/8y^7 which you then have to evaluate at some point. ------------------------------ h...
*October 6, 2014*

**AP Calc**

y^2 = x^2 + 4/x 2y y' = 2x - 4/x^2 y' = (2x^3-4)/x^2 * 1/2y = (x^3-2) / x^2y Now as long as y≠0, y'=0 when x=∛2 y(∛2) = ±√(∛4+4/∛2) = ±√(6/∛2) so that's ok. It looks like the only place with ...
*October 6, 2014*

**algebra**

Since F=k∆x, F/∆x is constant. So, if the unstretched length is Lo, 8/(76-Lo) = 14/(85-Lo) Lo = 64 cm
*October 6, 2014*

**Pre Calculus**

What part of your text's explanation don't you understand? Any explanation we can give here will say basically the same thing.
*October 6, 2014*

**Math**

plug in the values graph the function
*October 6, 2014*

**Math**

since y = 10/x, the slope of the tangent at (x,y) is -10/x^2 so the normal has slope x^2/10. So, we have a line with slope y/x = (10/x)/(x^2/10) = 100/x^3 so, where does 10/x = 100/x^3? x = √10 So, at (√10,√10), the slope is 1, and the normal line is just y = x
*October 6, 2014*

**Math**

Man, you're a better grouper than I am. The 18 made me think of 9*2, so I got x(x-3)^2 = x^3-6x^2+9x hmm. too many x^2, so 2(x-3)^2 = 2x^2-12x+18 aha - (x+2)(x-3)^2
*October 6, 2014*

**Algebra**

if a/b = q remainder r, then a = b*q + r Try it with some small numbers: 37/8 = 4R5 4*8+5 = 37
*October 6, 2014*

**Algebra2**

just solve the way you do an equation. Apply a step to all parts of the setup: -1 < 3+2x < 11 subtract 3: -4 < 2x < 8 divide by 2 -2 < x < 4 Ta-da! The other is even easier, since each is separate 1-x > -3 1+3 > x 4 > x 5x-1 > 19 5x > 20 x >...
*October 6, 2014*

**Algebra II**

We have a winner!
*October 6, 2014*

**Algebra II**

4(4x+1)^2 = 4(16x^2+8x+1) Better double-check your answer.
*October 6, 2014*

**Pre Calculus**

No, what it says is (x-c) is a factor of f(x). If (x-c) is a factor of f(x), then f(c) = 0 f(-2) = -4(-8)+5(4)+8 = 32+20+8 ≠ 0 So, (x+2) is not a factor of f(x). You can check this out at calc101.com by clicking on the "long division" button and entering your ...
*October 6, 2014*

**Pre Calculus**

I think you mis-stated the problem. Better go back and see just what the theorem says.
*October 6, 2014*

**math geometry**

As usual, draw a diagram. Half the chord is of length 4. Draw the radius through the chord's center. Now you have a right triangle with leg 4 and hypotenuse 8, which subtends an angle x such that sinx = 1/2 So, x = 30 degrees. The whole chord thus subtends an angle of 60 ...
*October 6, 2014*

**Math**

if f(ax) = af(x), f(x) = kx for some k. check: f(ak) = k(ax) = a(kx) = af(x) f(x+y) = k(x+y) = kx+ky = f(x)+f(y) So, since f(1) = pi, f(x) = pi*x f'(-1) = pi In fact, f'(x) = pi for any x.
*October 6, 2014*

**Math- AP Calc**

3x+xy+4y=8 3 + y + xy' + 4y' = 0 y'(x+4) = -(y+3) y' = -(y+3)/(x+4) y" = -[(y')(x+4)-(y+3)(1)]/(x+4)^2 = -[-(y+3)/(x+4)*(x+4) - (y+3)]/(x+4)^2 = -(-3-y-y-3)/(x+4)^2 = (2y+6)/(x+4)^2 check: 3x+xy+4y=8 y = (8-3x)/(x+4) y' = -20/(x+4)^2 y" = 40/(...
*October 6, 2014*

**Math Proof**

well clearly, since b_n is between 0 and a_n, as a_n->0, so does b_n. Not sure (b) follows. There must be some other conditions on the sequences.
*October 6, 2014*

**word problems**

since time = distance/speed, d/(12-2) = d/(12+2) + 1 d = 35 miles check: 35/10 = 3.5 35/14 = 2.5
*October 6, 2014*

**clemson**

If each pen is x by y, with the x side parallel to the river, then 6x+4y = 1680 a = 3xy = 3*x(1680-6x)/4 = (2520x-9x^2)/2 This is just a parabola with vertex (hence maximum area) at x = 140 So, each pen is 140 by 210 As usual, the fencing is divided equally between lengths and...
*October 6, 2014*

**Math**

not unless i√12 = √12 I think you meant 4±√-12 = 4±i√12 If so, then you are correct
*October 6, 2014*

**Geometry**

Now, if you meant to shift it 3 left and 8 down, then (8,3)+(-3,-8) -> (5,-5)
*October 6, 2014*

**Geometry**

singular is vertex, not vertice. Grr. (8,3) + (x-11,y-11) -> (x-3,y-8)
*October 6, 2014*

**math**

$591.12/72hr = $8.21/hr
*October 6, 2014*

**Algebra**

2x + 6/x = 79/5 10x^2 + 30 = 79x 10x^2 - 79x + 30 = 0 (5x-2)(2x-15) = 0 ...
*October 6, 2014*

**Pre-Calc/Trig...**

y = (x^2-4x+4) - 5+4 = (x-5)(x+1)
*October 6, 2014*

**math**

3(u-2) = 4(u+3) 3u-6 = 4u+12 u = -18 check: -20/-15 = 4/3 yes
*October 6, 2014*

**Math, ASAP Please**

Looks like D to me. Sheesh!
*October 6, 2014*

**Calculus**

depends on where the man is. If the man's distance is x, and the shadow has length s, then (x+s)/15 = s/6 Now just differentiate and plug in the distance when you finally deign to include it.
*October 6, 2014*

**Timerate problem(calculus)**

v = 1/3 pi r^2 (2r) = 2/3 pi r^3 at r=8, dv/dt = 2 pi r^2 dr/dt Now we just have to decide what "at what rate is the increasing" means
*October 6, 2014*

**math**

because 1/5 = 5^-1
*October 6, 2014*

**ALGEBRA**

It will take x days, where 1/x = 1/10 + 1/12
*October 6, 2014*

**Maths**

Apparently the sides are in the ratio b = 3/5 (a+c) c = 1/7 (a+b) a^2 = 144 a,b,c = 12,9,3 so, area = 144+81+9 = 234
*October 6, 2014*

**Maths**

If the bottles cost $x each, then 7x + 13.20 = 10x
*October 6, 2014*

**geometry**

(40-2*2)(20-2*2) = ?
*October 6, 2014*

**Math**

4/7
*October 5, 2014*

**Math**

no way to tell. How tall is the human?
*October 5, 2014*

**Algebra**

well, just plug in the points: a|1-b|+c = 4 a|3-b|+c = 8 a|8-b|+c = 3 a = -2, b = 17/4, c = 21/2
*October 5, 2014*

**Algebra**

a good site for long division is calc101.com Click on the long division button, and you can see all the details.
*October 5, 2014*

**Calculus**

As you can see from the graphs at http://www.wolframalpha.com/input/?i=plot+y%3De^%282x%29%2C+y%3D2x you missed the mark. So, let's see what happened. At the point (x,y) on the curve, the slope is 2e^(2x). A line with slope 2e^(2x) through the origin: e^(2x)/x = 2e^(2x) x...
*October 5, 2014*

**math factoring**

2x^4+12x^3-18x^2-108x 2x(x^3+6x^2-9x-54) Now use grouping 2x(x^2(x+6)-9(x+6)) 2x(x^2-9)(x+6) 2x(x-3)(x+3)(x+6)
*October 5, 2014*

**Math**

g'(x) = f(x^2) + xf'(x^2)(2x) = f(x^2) + 2x^2 f'(x^2) So, at x=2, g'(2) = f(4) + 8f'(4) = 4+8(-3) = -20 g(2) = 2f(4) = 8 So, now we have a point and a slope: L(x) = -20(x-2) + 8 = -20x+48
*October 5, 2014*

**Math**

A = 4pi r^2 dA = 8pi r dr Now plug in the numbers. Recall that % error is dA/A * 100
*October 5, 2014*

**math**

Hint: The only common divisors of 24 and32 are 2,4,8
*October 5, 2014*

**9th grade algebra**

Are you German? What's With All The Capitalization? The lope of the line is (190-120)/2 = 35 y = 50 + 35x
*October 5, 2014*

**Math**

at depth y, the radius of the water surface is r = (10/22)x = 5/12 x So, at depth y, the volume of water is v = 1/3 π (5/12 y)^2 = 25/432 π y^2 dv/dt = 25/216 π y dy/dt 30 = 25/216 π (14) dy/dt 30 = 5.08 dy/dt dy/dt = 5.89 ft/min As always, check my math.
*October 5, 2014*

**statistics**

Seems to me just like drawing from a pack of cards without replacement. p = 136/500 * 135/499 * 134/498 = 0.0198
*October 5, 2014*

**solve long divison polynomials**

A good site for long division is ath calc101.com Just click on the "long division" tab to see all the details, in proper formatting.
*October 5, 2014*

**cobet, maths**

Umm, didn't you just say that 33 like both?
*October 5, 2014*

**calculus**

First off, I suspect a typo. Why have two y^2 terms? I figure you meant x^2 + 4xy +4y^2=40 Just do things term by term, and don't forget the product rule: 2x + 4y + 4xy' + 8yy' = 0 y'(4x+8y) = -(2x+4y) y' = -1/2 Weird, huh? Not if you note that x^2 + 4xy +...
*October 5, 2014*

**math**

Ummm. First off, what do M and O have to do with the length of AB?
*October 5, 2014*

**Math**

4x^2+4y^2-8x-20y+13=0 rearrange things a bit and you get 4x^2-8x + 4y^2-20y = -13 4(x^2-2x) + 4(y^2-5y) = -13 Now complete the squares: 4(x^2-2x+1) + 4(y^2-5y+25/4) = -13 + 4(1) + 4(25/4) 4(x-1)^2 + 4(y - 5/2)^2 = 16 (x-1)^2 + (y - 5/2)^2 = 4 Now does it look familiar?
*October 5, 2014*

**Math**

what's to solve? You have just defined a function.
*October 5, 2014*

**physics**

The situation can be modeled as though the 1st tank were stationary, and the 2nd tank were retreating at 20 m/s. The horizontal and vertical components of the shell's speed at firing are x: 43.4 m/s y: 246.2 m/s So, the height of the shell is h(t) = 246.2t - 4.9t^2 It hits...
*October 5, 2014*

**Algebra**

father's age is f. My age is m. (f-4) = 4(m-4) f+m = 53 Now just solve for f and m.
*October 5, 2014*

**Pre-Calc**

well, it's just f(x)/g(x) = (1/x)/(x^3) = 1/x^4 And I'm sure you can figure the domain. It's where the denominator is not zero.
*October 5, 2014*

**Math**

clearly, it's b and c try dividing out the x^2 factor
*October 5, 2014*

**Calculus**

You have ∫√(u^2-a^2) du, so set u = a secθ du = a secθ tanθ u^2-a^2 = a^2 tan^2θ so it becomes ∫ (a tanθ)(a secθ tanθ) dθ = a^2∫secθ tan^2θ dθ = a^2∫sec^3θ - secθ dθ Now, we all...
*October 5, 2014*

**Calculus**

well, if y = sin^2(u) y' = 2 sinu cosu u' u' = ln3 3^x y' = 2ln3 3^x sin(3^x) cos(3^x) = ln3 3^x sin(2*3^x) I think you got some of your 3's mixed up as powers of sin. You appear to have taken the derivative of sin^3 (3^x)
*October 5, 2014*

**Algebra 2 (Please, help me!)**

Take |x| shrink it horizontally by a factor of 2: |2x| shift it down 3: |2x|-3 Now shrink it vertically by a factor of 4: (|2x|-3)/4 http://www.wolframalpha.com/input/?i=plot+y%3D|x|%2C+y%3D%28|2x|-3%29%2F4
*October 4, 2014*

**Math**

Since the border is on both sides, 5 + 2(2 1/4) = 9.5 7 + 2(2 1/4) = 11.5 2(9.5+11.5) = 42
*October 4, 2014*

**Math**

X^2+4x=10 x^2+4x+4 = 10+4 (x+2)^2 = 14 x+2 = ±√14 x = -2±√14
*October 4, 2014*

**Math**

that will of course be x miles where 100+.60x = 50+.80x
*October 4, 2014*

**algebra**

How could a quadratic be anything like a linear function?
*October 4, 2014*

**algebra**

You could think of it as a shifted parabola, where 2x+3(x-2)^2 = 3(x-2)^2 + 2(x-2) + 4
*October 4, 2014*

**algebra**

Is there a question in there somewhere?
*October 4, 2014*

**Calculus**

the indicated line has slope -1. y' = 6x+4 6x+4 = -1 when x = -5/6 y(-5/6) = -5/4 So, the line is y = -(x+5/6) - 5/4 http://www.wolframalpha.com/input/?i=plot+y%3D3x^2%2B4x%2C+y+%3D+-%28x%2B5%2F6%29+-+5%2F4
*October 4, 2014*

**Physics**

How long does it take to drop 785m? 4.9t^2 = 785 Then the horizontal distance traveled in that time is 53.5t
*October 4, 2014*

**Algebra**

z- 1/5 > 1/4 My answer is z < 9/20
*October 4, 2014*

**Physics**

think on it. If the angle of elevation is 0, a = 0 if x = 90 degrees, a = g So, what trig function has its zero at x=0, and its max at x = 90 degrees?
*October 4, 2014*

**Algebra**

If m play in marching band, then m+250-130 = 375 m = 255 How did you arrive at 135? I can see 125, but not 135. Anyway, the question was not "how many play only in the marching band?"
*October 4, 2014*

**math**

Let x be the number of 10-person increases. So, since revenue is price*people, R(x) = (200+10x)(30-1.50x) That is just a parabola, with its vertex midway between the roots, at x = (-20+20)/2 = 0 That is, max revenue for just 200 people. That is assuming that the price decrease...
*October 4, 2014*

**Algebra**

3*85 <= 83+91+x <= 3*90 255 <= 174+x <= 270 81 <= x <= 96
*October 4, 2014*

**Algebra**

correct. But I suspect that was not really the question. If the question was asking for P', then that would be {2,4,6,8} When talking about sets, it's better to use the braces; otherwise, you just have a list, not a set.
*October 4, 2014*

**Algebra**

Hmmm. You think 5 is a factor of 16? If so, you need to review the term "factor". Better prune your list a bit.
*October 4, 2014*

**AP Statistics**

From the Z table, the 10% tail is 1.282 std from the mean. Since the 10% tail is used on both ends, the mean is halfway between where the tails start. That help?
*October 4, 2014*

**algebra**

x=1, y=2: x+y=3, 3x+2y=9 (8)(9)(x+y)/(3x+2y) = 24
*October 4, 2014*

**Science**

correct again.
*October 3, 2014*

**Physics**

Oops -- v = -9.8t
*October 3, 2014*

**Physics**

horizontal speed is constant: 30.9/3.03 m/s The vertical speed is v = at = -4.9t The angle x is such that tan(x) = Vy/Vx
*October 3, 2014*

**Physics**

the height is h(t) = 20.7t - 4.9t^2 That's just a parabola; the max height is at the vertex. Now just solve for t when h=0. To save yourself some work, the max height is reached at the center of its flight, so you really only need to calculate one of the above answers, ...
*October 3, 2014*

**Science**

You are correct.
*October 3, 2014*

**math**

6^2 = 36 1+3+5+7+9 = 25 + 4 = 29 2^5 = 32
*October 3, 2014*

**math**

200 * 0.1 = ? Ever hear of a calculator?
*October 3, 2014*

**Math**

True, but we also have (a+9)(a+16) = a^2 + 25a + 144
*October 3, 2014*

**one last difference (math)**

I think you need to reword your question. 1.2 is the fraction less than 1.8 Now, if you want to know how much less than 1.8 1.2 is, then of course that would be 1.8-1.2 = 0.6
*October 3, 2014*

**math**

So, did you use the table?
*October 3, 2014*

**math 156**

P(1+.04/4)^(4*6) = 35000 Now just solve for P.
*October 3, 2014*

**math**

Just match the values in pairs. A. Each pair adds up to 1002 B. Each pair adds up to 100 Now just figure out how many pairs there are.
*October 3, 2014*

**algebra 2**

x=9 2x+3y = 30 Now the rest of the questions get easier.
*October 3, 2014*

**pre-calc**

Clearly, since we have a semicircle, the width of the rectangle is half the length. So, A = (3x/2)(3x) P = 2(3x/2 + 3x)
*October 3, 2014*

**Physics**

If you are not familiar with the equations for trajectories, the wikipedia article for that subject has a good treatment. Just plug in your values for the equation of motion, and crank it out. If you get stuck, come on back with your work so far, and we can give you a nudge in...
*October 3, 2014*

**Math**

In that case, review your basic trig functions. cos(x) = 7/21 Now just find x, with that value for cosine.
*October 3, 2014*

**Pre-Calc/Trig...**

No idea. But the answer is clearly B, if for no other reason than that x and y have opposite signs on the left.
*October 3, 2014*

**Pre-Calc/Trig...**

recall the point-slope form of a line. In this case, y-1 = 3(x-10) Now massage that into one of the choices.
*October 3, 2014*

**houston community college**

Since PV=kT, PV/T is constant. So, since P is constant, V/T is constant. That means: 1.4/(27+271) = V/(177+271)
*October 3, 2014*

**Calc**

I don't know what the original problem was, but if the doubling time is 24 days, the formula for the amount present after t days is A(t) = Ao * 2^(t/24) Since 2 = e^ln2, that is equivalent to A(t) = Ao * e^(ln2/24 t)
*October 3, 2014*

**AP CALC. AB**

f(x) = 3/x f'(x) = -3/x^2 So, we want -3/c^2 = 3(-3/4) c^2 = 4/3 ...
*October 3, 2014*

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