Monday

September 26, 2016
Total # Posts: 44,087

**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*

**algebra**

82.4 <= f <= 659.2

*September 4, 2016*

**maths**

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

*September 4, 2016*

**Math**

when you have no clue, try google first: https://answers.yahoo.com/question/index?qid=20090501152219AAtVxte

*September 4, 2016*

**Math**

Clearly the T can occur in any of the 3 positions.

*September 4, 2016*

**Math**

any of 18 different numbers can show on each roll. So, there are 18*18*18 different sets of 3 events

*September 4, 2016*

**Pre cal**

I assume you get this far ok: ... (x-4)(x^2+4) x^3-4x^2+4x-16 evaluate that at x = -1, and you get -1-4-4-16 = -25 That means that if f(x) = a(x^3-4x^2+4x-16) then f(-1) = -25a But, we want f(-1) = -50 so, -25a = -50 a = 2 f(x) = 2(x^3-4x^2+4x-16)

*September 4, 2016*

**Math**

wait - we doing heights or lengths? anyway, average = sum/count

*September 4, 2016*

**yuiljk**

200/50 + 1

*September 4, 2016*

**Physics**

subtract the area of the hole from that of the disc rim; then multiply by the thickness: π(128^2 - 15^2)(0.75) mm^3

*September 4, 2016*

**Math**

it will be the same as when it went up.

*September 4, 2016*

**Basic Math**

yes, it would.

*September 4, 2016*

**Computer science**

If you haven't already written your own routine, google one of your choosing. You should "zero" in on n ≈ 19.2681

*September 4, 2016*

**Physics**

work = force * distance the mass does not matter; it just affects how long it will take.

*September 4, 2016*

**MATH**

1 * 26^3 * 10^2

*September 4, 2016*

**Algebralgebrad**

no, 1+tanx is not the same as 1+tan^2x use your sum-to-product formulas: cosx-cosy = -2 sin(x+y)/2 sin(x-y)/2 sinx+siny = 2 sin(x+y)/2 cos(x-y)/2 so the quotient is just -tan(x-y)/2 the 2nd term is similar recall that (a+b)^3 = (a+b)(a^2-ab+b^2) csc2x = 1/sin2x = 1/(2sinx cosx...

*September 4, 2016*

**Math**

since 24 = 6*2^2 any multiple of 6 that does not also have 2 as a factor: 6*1=6 6*3=18 6*5=30 6*7=42 etc.

*September 4, 2016*

**algebra**

as with any cone, v = π/12 d^2 h

*September 4, 2016*

**mathematics - algebra**

well, tanθ >= 121/915, so ...

*September 4, 2016*

**Pre Calc**

http://www.wolframalpha.com/input/?i=-x%5E2%2B9x-8

*September 4, 2016*

**Math**

30*4.2 -------- 5/3

*September 4, 2016*

**math help**

y = x^2/2 y' = x so, the line through (3,9/2) with slope=3 is y - 9/2 = 3(x-3)

*September 4, 2016*

**Math**

5/20 = ...

*September 4, 2016*

**Trignometric**

2tan^2(x) + sec^2(x) = 5 - 4tan(x) 2tan^2(x) + 1+tan^2(x) = 5 - 4tan(x) 3tan^2(x) + 4tan(x) - 4 = 0 (tanx+2)(3tanx-2) = 0 Now you know tan(x) cot(a+b) = 6 (cota*cotb-1)/(cota+cotb) = 6 cota = -2, so (-2cotb-1)/(-2+cotb) = 6 -12cotb-6 = -2+cotb -4 = 13cotb cotb = -4/13 or, use ...

*September 4, 2016*

**algebra**

how many o's? how many total letters?

*September 4, 2016*

**Math**

south: 120 cos46° west: 120 sin46°

*September 4, 2016*

**Algebra**

y = k/x 2 = k/6 ...

*September 4, 2016*

**Math**

I'll use x for ease of typing each turkey cost x.xx/72 72*x.xx = x67.9x start listing multiples of 72 that end in 9x: 72*11 = 792 72*18 = 1296 72*36 = 2592 Check to see which works out

*September 3, 2016*

**MATH**

x+y+z = x*y*z 1+2+3 = 1*2*3 ...

*September 3, 2016*

**physics (Simple harmonic motion)**

assuming t is in seconds, I don't see how to get 37.963m http://www.wolframalpha.com/input/?i=0.142sin(2t%2B0.19)+for+0%3C%3Dt%3C%3D210 unless t1 is not zero

*September 3, 2016*

**Calculus**

of course, the range is just the same as the range of 2sin(x)+3: [1,5] http://www.wolframalpha.com/input/?i=2sin(sqrt(3x-1))+%2B+3

*September 3, 2016*

**Calculus**

no idea. Just take it step by step. domain of √x is x>=0 so, the domain of √(3x-1) is 3x-1 >= 0, or x >= 1/3 the domain of sin(x) is all reals, so the domain of sin(√(3x-1)) is the domain of √(3x-1), or x >= 1/3

*September 3, 2016*

**Calculus**

that's a start. Now consider that 4 = 2^2 8 = 2^3 So, log_4(8) = (1/2)log_2(8) = 3/2 log_8(16) = (1/4)log_2(16) = 4/3 (3/2)/(4/3) = 9/8

*September 3, 2016*

**Calculus**

e^(1+2lnx) = e^1 * e^2lnx = e * (e^lnx)^2 = e * x^2 That should help some Tsk Tsk, Damon

*September 3, 2016*

**math**

The latus rectum's length is 2 times the distance from the focus to the directrix. Now recall the point-to-line distance formula, and you get |3*1-4*1+7|/√(1^2+1^2)

*September 3, 2016*

**Math**

as you know, the domain of sin(x) is (-∞,∞) The domain of √x x>=0 so, the domain of √(3x-1) is 3x-1 >= 0, or x >= 1/3 so, can you sort that out?

*September 3, 2016*

**Math**

well, geez! How many factors of 16 are there between 6 and 15?

*September 3, 2016*