Sunday

September 25, 2016
Total # Posts: 44,023

**Algebra**

you want w when 900+10w = 500+15w

*September 6, 2016*

**physics**

You sure are cagey with the names of your vectors. I'll call them u,v,w. Just draw a diagram. It should be clear that the x- and y-components of vector u are x: -113 cos34° y: 113 sin34° Do the others the same way. For magnitudes, recall that |<x,y>| = √...

*September 6, 2016*

**science**

many discussions found via https://www.google.com/#q=electric+field+at+center+of+circular+arc

*September 6, 2016*

**Math Please Help Me**

just think about it. How much clay was used? 1 1/2 + 3/4 = 1 2/4 + 3/4 = 1 5/4 = 9/4 lbs Now, if each student uses 1/8 lb, the 1 whole pound is enough for 8 students, right? So 8 * 9/4 = 72/4 = 18 students can be satisfied. Or, since 1/4 lb = 2/8 lb, each 1/4 lb of clay will ...

*September 6, 2016*

**algebra 2**

Mary has a 2-hr start, so she's 120 mi ahead at 8 am. Tom hoes 10 mi/hr faster, so how long will it take him to make up the 120 mi?

*September 6, 2016*

**maths**

wow - can you make heads or tails of that gibberish? I assume that 22-60 means 22°60'. No idea what "tita" means. Must be "theta". At any rate, since the circumference of the earth is about 40,000 km, the plane flew 8000km = 1/5 of the way around ...

*September 6, 2016*

**Math**

just think about it. How much clay was used? 1 1/2 + 3/4 = 1 2/4 + 3/4 = 1 5/4 = 9/4 lbs Now, if each student uses 1/8 lb, the 1 whole pound is enough for 8 students, right? So 8 * 9/4 = 72/4 = 18 students can be satisfied. Or, since 1/4 lb = 2/8 lb, each 1/4 lb of clay will ...

*September 6, 2016*

**Math**

rate per hour is #dollars / #hours (1 1/2 + 3/4)/(1/8) or 8 * (3/2 + 3/4) = ?

*September 6, 2016*

**Math**

uh, -12/1

*September 6, 2016*

**Algebra1**

#1 D is correct #4 B is correct, but the rate of change of f is 2/3, and of g is -3/4 #10 A is correct #1 I agree. Must be a typo. f(1)+g(2) = 4, however #2 C is correct

*September 6, 2016*

**math**

start with volume = mass/density find the density of each liquid, and you can figure the volume. Then volume = arae * height You know the area of the liquid cross-section, so once you know the total volume, the height is height = volume/area

*September 6, 2016*

**Technology**

seems to me that R T G V F are done with the left index finger

*September 6, 2016*

**Math**

Huh? 10+2.5x = 25 2.5x = 15 ...

*September 6, 2016*

**Math**

After x years, the height y is y = 10 + 2.5x So, find x when y=25

*September 6, 2016*

**Math**

Ths distance of (x,y) from the y-axis is just x. So, √((x-2)^2 + (y-3)^2) = x (x-2)^2 + (y-3)^2 = x^2 x^2-4x+4 + (y-3)^2 = x^2 (y-3)^2 = 4x-4 (y-3)^2 = 4(x-1) as I showed using the properties of parabolas

*September 6, 2016*

**Math**

review the definition of a parabola. The standard equation is y^2 = 4px if the focus is at (p,0) and directrix x = -p So, you have to shift your axes giving you (y-3)^2 = 4(x-1) see http://www.wolframalpha.com/input/?i=parabola+(y-3)%5E2+%3D+4(x-1)

*September 6, 2016*

**Calculus**

I don't think we need to use the Laplace transform, since they are specifying V(t) as a piecewise function. Just specify two values for V to the left and right of t=3

*September 6, 2016*

**business studies**

what do you mean by "solve time"? And no, 45÷60 = 3/4

*September 6, 2016*

**Geometry**

come on. I did that! The two angles are equal, so the two expressions are equal. <DGI = <IGH x-3 = 2x-13 x = 10

*September 6, 2016*

**Geometry**

since GI bisects <DGH, <DGI = <IGH so, x-3 = 2x-13

*September 6, 2016*

**Math Precal**

Carefully draw the two vectors, placing the start of the wind vector at the end of the plane's vector. If you draw in some dotted axes, you can see that the angle between the vectors (geometric, not algebraic) is 90-30-15 = 45° The ground speed of the plane is found ...

*September 6, 2016*

**Math**

4 times the area means 2 times the side length. So, if x is the smaller side, 4x + 4(2x) = 5

*September 6, 2016*

**Math*Coordinate Geometry ~the Challenge Test Your Skill People.**

y = k(x+4)(x-3) now plug in x=0 to find z. z = -12k k = -z/12 So, y = -z/12 (x^2+x-12) = -z/12 x^2 - z/12 x + z so, for each z there is only one possible value for each of a,b,c

*September 6, 2016*

**algebra**

(7+2.5)m^2 + (6.5-4-1)n now just add up the numbers

*September 6, 2016*

**algebra 1**

Assuming you meant (0,3) then yes, it is a solution, since 0+3=3 -2(1) = -2 so (1,-4) is not a solution you are backwards again. I think you need to review what a solution is. You have answered all three questions exactly wrong.

*September 6, 2016*

**Math**

when dividing, subtract exponents, so you have c^(9-14) d^(-7-(-10)) = c^-5 d^3 or d^3/c^5

*September 6, 2016*

**physics simple harmonic motion**

http://www.wolframalpha.com/input/?i=15+sin(8%CF%80(t%2B.1250398))

*September 6, 2016*

**physics simple harmonic motion**

x(t) = 15 sin(8πt+Ø) at t=0, x=0.015, so 15 sin(0+Ø) = 0.015 sinØ = 0.001 for small Ø, sinØ = Ø so I'd say x(t) = 15 sin(8πt+0.001) = 15 sin(8π(t+.0000398)) so it appears that Ø=.0000398 But, x'(0) < 0...

*September 6, 2016*

**math**

1/4 + 1/3 + 1/6 = 3/12 + 4/12 + 2/12 = 9/12 = 3/4 that's how much the three ate.

*September 6, 2016*

**math**

not same as -3 ≠ 3

*September 6, 2016*

**math please help asap**

4+2x=7

*September 6, 2016*

**algebra 1**

nope. That is the solution to 3x = 24

*September 6, 2016*

**Geometry**

all correct

*September 6, 2016*

**Pure Math Coordinate Geometry**

Yes, you can say A is 1/3 of the way from B to O That's the same as saying A is 2/3 of the way from O to B.

*September 6, 2016*

**Pure Math Coordinate Geometry**

because OA:AB = 2:1 Draw the line OB of length 3 Mark point A such that OA=2 AB=1 A is 2/3 of the way from O to B

*September 6, 2016*

**Pure Math Coordinate Geometry**

A is 2/3 of the way from O to B. So, the x- and y-values are 2/3 of the way from (0,0) to (6,9). That help some?

*September 6, 2016*

**Science**

first, g is m/s^2, not m/s F = GmM/r^2 = 9.8m you have a new R=100/64 r = 25/16 r So, g will be (16/25)^2 as big 9.8 * (16/25)^2 = 4.01 m/s^2

*September 6, 2016*

**Math**

Hmmm. I get 10 m^(5/3) n^(1/8)

*September 6, 2016*

**Physics**

how long does it take to land? 4.9t^2 = 10 Use that t to determine horizontal distance, which is d = 8t I must say, 10m is not much of a cliff...

*September 6, 2016*

**Physics**

huh? v1 = <-6.6,0> don't get so bogged won in formulas that you fail to recognize simple geometry! If you must rely on the formulas, note that θ=180°

*September 6, 2016*

**algebra**

start by grouping digits 10,000,000,000,000,000,000,000,000,000,000 Now figure out the name of the group you want.

*September 6, 2016*

**math**

Nope: y = 4x+5

*September 6, 2016*

**Astronomy**

how far is it from the sun to the earth? That is 1 a.u.

*September 6, 2016*

**Trig**

I hope you got sinA = 3/5 cosA = 4/5 tanA = 3/4 sinB = 15/17 cosB = 8/17 tanB = 15/8 given that, then sin(A+B) = 3/5 * 8/17 + 4/5 * 15/17 = 84/85 cos(A+B) = 4/5 * 8/17 - 3/5 * 15/17 = -13/85 tan(A+B) = 84/-13 = -6.46 it might have been nice to see where you went wrong there. ...

*September 6, 2016*

**Maths**

1/x + 1/y + 1/z = 1/15 x = 2(y+z) y = 3(x+z) Hmmm. I suspect a typo.

*September 5, 2016*

**Math**

30/18 5/3 15000/9000

*September 5, 2016*

**math**

well, f(x) = (x^2-5)(x^2+3) ...

*September 5, 2016*

**math**

if the short leg is x, then x^2 + (x^2-5)^2 = (2x^2-13)^2

*September 5, 2016*

**Algebra**

oops. for raw increase, 42/300 * 3

*September 5, 2016*

**Algebra**

42/300 * 3/30

*September 5, 2016*

**Math urgent**

(x+y)^2 - 2(x+y) - 15 = 0 (x+y-5)(x+y+3) = 0 ...

*September 5, 2016*

**Pre algebra**

y = kx, so 17 = 34k

*September 5, 2016*

**math**

18/72 = ?

*September 5, 2016*

**Math**

2π ≈ 6 40/6 ≈ 7 what do you think?

*September 5, 2016*

**Pre algebra**

y = k/x, so plug in your numbers: 8 = k/5

*September 5, 2016*

**Calculus**

the normal to the plane has direction cosines proportional to <1,-1,2>, so x = 4+t y = 1-t z = 4+2t xy-intercept: z=0, so t = -2 (2,3,0) and so on

*September 5, 2016*

**Calculus**

mosey on over to http://math.stackexchange.com/questions/475953/how-to-calculate-the-intersection-of-two-planes and have a gander there.

*September 5, 2016*

**MATH HELP CHECK ANSWER**

7-3 < x < 7+3 4 < x < 10 So, B or C looks good

*September 5, 2016*

**Math**

factor out the highest powers common to both factors: x^2y^2 (xy^2 + 1)

*September 5, 2016*

**Math Please Help**

your screen name reminds me of this one: aibohphobia: fear of palindromes

*September 5, 2016*

**Math Please Help**

much better

*September 5, 2016*

**Math Please Help**

oops. #5 the area is 3^2 times as big.

*September 5, 2016*

**Math Please Help**

5 ok 6 huh? How can a parabola have three roots? Did you try graphing it? Remember the quadratic formula? recall that an nth degree polynomial has at most n real roots

*September 5, 2016*

**Science**

under what conditions? If you just want the energy equivalent, then use the good old formula E = mc^2 using the appropriate SI units

*September 5, 2016*

**MATH HELP PLEASE ASAP**

Just to refresh your memory on why this is true, the distance from a to b is b-a the value halfway from a to b is thus a + (b-a)/2 = (2a+b-a)/2 = (a+b)/2

*September 5, 2016*

**MATH HELP PLEASE ASAP**

the midpoint has the average coordinates of the ends: ( (4+0)/2 , (-4+5)/2 ) = (2,1/2)

*September 5, 2016*

**math**

there's nothing to distribute a(b+c) = ab + ac uses the distributive property You can, however, apply the power to each factor individually

*September 5, 2016*

**Science**

max height is reached when it comes to a stop v = 14-gt solve for t when v=0 and use that to find h in h = 14t - g/2 t^2 Or, use (or derive) a simpler more direct formula without finding t first.

*September 5, 2016*

**chem 2**

first step: write the balanced equation next, use moles instead of grams

*September 5, 2016*

**Trigg**

recall your polar coordinates x = r cosθ y = r sinθ here, θ is in QIII

*September 5, 2016*

**Calculus**

If you recall the determinant form of the triple product, you will see that both are zero, since two rows of the determinant are the same.

*September 5, 2016*

**Math**

a = ∆v/∆t = (60-30)/7 m/s^2

*September 5, 2016*

**Calculus**

The center is at (6,6,6) The diameter has length √12=2√3 so, the sphere is (x-6)^2 + (y-6)^2 + (z-6)^2 = 3 It'd be better in the future if you provide some of your work when you get stuck.

*September 5, 2016*

**maths**

It's not. Having a square root is. √x = x^(1/2) 1/√x = x^(-1/2) Your assertion is true if you are solving for a, since to find a you need to take the square root.

*September 5, 2016*

**Physics**

First, I'd say, since when is 50 bigger than 140?

*September 5, 2016*

**calculus**

F' = f'(xf(xf))*(f(xf)+xf'(xf)(f+f(xf'))) = f'(f(f(1)) * (f(f(1))+f'(xf(1))(f(1)+f(f'(1))) = f'(f(4))*(f(4)+f'(4)(4+f(4))) = f'(6)(6+5(4+6)) = 6(6+50) = 6*56 = 336

*September 5, 2016*

**math**

If there are x apples and y oranges, we know that x/y = 2/3 (1/3 x)/(y-23) = 3/2 Now just solve for x

*September 5, 2016*

**math**

r^2-x^2 = 4^2 r^2-(4-x)^2 = 3^2 now just solve for r

*September 5, 2016*

**calculus**

y(6) = 36A+6B = 8 y' = 2Ax+B y'(6) = 12A+B = 7 Now just solve for A and B.

*September 5, 2016*

**Chemistry**

Why is it important to keep the beaker containing the mobile phase covered while preparing your chromatography paper and developing your chromatograms?

*September 5, 2016*

**math**

b+g=53 3/5 b + 5/7 g = 35 or, knowing that g is a multiple of 7 b is a multiple of 5 how many such multiple pairs add to 53?

*September 5, 2016*

**Math**

xx.x66xxx

*September 5, 2016*

**math**

3/4 as many people: 4/3 as many hours

*September 5, 2016*

**Statistics**

well, 70 is 2 std above the mean. Look that up in your Funk and Wagnall's (or, more productively, in your Z table).

*September 5, 2016*

**MATH**

5*8 + 4*10

*September 5, 2016*

**profit and loss**

1.20x + 1.2 = 1.40x

*September 5, 2016*

**math**

(2(n+5)-10)/2 = n

*September 5, 2016*

**profit and loss**

.55*1.05 + .45*1.08 = 1.0635 .45*1.05 + .55*1.08 = 1.0665 so, what is the % change? The amount invested does not matter, since it is all the same.

*September 5, 2016*

**math**

let's just call 4/3 pi = k since it does not depend on r. v(2r)/v(r) = k(2r)^3/kr^3 = 8kr^3/kr^3 = 8

*September 5, 2016*

**Calculus**

come on - you did this for 2D figures back in Algebra II: x^2+4x + y^2-2y + z^2-2z = 19 x^2+4x+4 + y^2-2y+1 = z^2-2z+1 = 19+4+1+1 (x+2)^2 + (y-1)^2 + (z-1)^2 = 25

*September 4, 2016*

**Math**

since -1 <= sin(u) <= 1 e^x -> +∞ 1/∞ = 0 as x -> +∞ But, oddly enough, this only a one-sided asymptote, since e^-∞ = 0, e^x-2 -> -2 as x -> -∞ And of course, there is the vertical asymptote at x = ln(2) http://www.wolframalpha....

*September 4, 2016*

**calculus**

yeah - where f'(x) = 0 f'(x) = -10sinx + 10cos2x now just find where that is zero

*September 4, 2016*

**calculus**

Let's take this a step at a time F' = f'(xf(xf(x))) * (xf(xf(x)))' (xf(xf(x)))' = f(xf(x)) + xf'(xf(x)) f'(xf(x)) = f(x) + xf'(x) so: F'(1) = f'(1f(1f(1))) * (f(1f(1)) + f(1)+f'(1)) = f'(f(4)) * (f(4)+f(1)+f'(1)) = f'(6...

*September 4, 2016*

**calculus**

clearly there are none.

*September 4, 2016*

**Math**

put it where? 2.0*10^-7 / 8.0*10^-9 = (2.0/8.0)*10^(-7 - (-9)) = 0.333 * 10^2 100/3

*September 4, 2016*

**Math**

still no ideas of your own? Try google when you have no clue: http://math.stackexchange.com/questions/202679/sum-of-digits-and-product-of-digits-is-equal-3-digit-number

*September 4, 2016*

**Algebra**

same as always (1+(2i/n))^2 *(2/n) (1 + 2(2i/n) + (2i/n)^2) * (2/n) 1(2/n) + 2(2i/n)(2/n) + (2i/n)^2(2/n) 2/n + 8i/n^2 + 8i^2/n^3

*September 4, 2016*

**Math Algebra**

A is the same distance from (1,3) as B is. You don't need to know that the distance is √29. You just need to subtract the same values from (1,3) as were added to get to (4,-1) (1,3)+(3,-4) = (4,-1) So, you need (1,3)-(3,-4) = (-2,7)

*September 4, 2016*