Friday

May 6, 2016
Total # Posts: 40,202

**5th grade math**

y < 2x y < 2*15 y < 30
*May 5, 2016*

**math**

(6.4+12.3)/2 h = 37.4 9.35h = 37.4 h = 4
*May 5, 2016*

**math**

better use Heron's formula, if all you have is the sides.
*May 5, 2016*

**Pre calculus**

sinθ = √((1-cos2θ)/2) = √(1/8) since 2θ is in QIV, θ is in QII
*May 5, 2016*

**Algebra**

both ok
*May 5, 2016*

**mason**

There are 7C2 = 21 ways to pick the 1st two horses, leaving 5 to arrange in the other places. So, there are 21 * 5! ways to finish the race.
*May 5, 2016*

**Math**

oops - 3/10 of 2/3 = 2/10 = 1/5 1/3 + 1/5 = 8/15 so, 7/15 x = 35 x = 75 check: on Monday read 1/3, or 25 pages, leaving 50 unread On Tuesday read 3/10 of 50 = 15 pages, leaving 35 unread
*May 5, 2016*

**calculus help me plz**

dx/((x-1)sqrt(x^2-2)) OK. First step is a trig substitution. x = √2 sec(u) x^2-2 = 2tan^2(u) dx = √2 sec(u) tan(u) du now the integral is sec(u)/(√2 sec(u)-1) du see what you can do with that.
*May 5, 2016*

**alebra**

both look good.
*May 5, 2016*

**trigonometry**

review your basic trig functions. You will see that the height is 38tan67°30' + 38tan18°20'
*May 5, 2016*

**math**

If the amount poured is x gallons, then (35-x)/(4.5+x) = 7/2 find x, and the rest is easy.
*May 5, 2016*

**math. compounding interest**

3500 * .075/2
*May 5, 2016*

**math**

use your distance formula: √(5^2+8^2)
*May 5, 2016*

**math**

clearly, since the box has length 8, the paper must be longer.
*May 5, 2016*

**Trigonomentry**

Draw a diagram. If we label the triangle ABC, with sides a,b,c then the law of sines tells us sinC/10.2 = sin117.5°/35 Now you have angles B and C, so you know A=180-(B+C) a/sinA = sin117.5°/35 or a^2 = 35^2+10.2^2 - 2*35*10.2 cosA
*May 5, 2016*

**help maths partail sum**

∑ 1/(6k-2) This is just a modified harmonic series, so it diverges. That is, you know that ∑ 1/k diverges. So, this does as well. Don't know a formula for the nth partial sum.
*May 5, 2016*

**Math**

just plug in your calculator. What do you get?
*May 5, 2016*

**calculus plz help me**

dx/((x-1)sqrt(x^2-2)) OK. First step is a trig substitution. x = √2 sec(u) x^2-2 = 2tan^2(u) dx = √2 sec(u) tan(u) du now the integral is sec(u)/(√2 sec(u)-1) du see what you can do with that.
*May 5, 2016*

**calculus plz help me**

see the steps here. http://www.integral-calculator.com/ Interestingly, wolframalpha.com simplifies it a lot.
*May 5, 2016*

**Math**

Review your basic trig functions. The height is 1.15 + 95.5tan31.5°
*May 5, 2016*

**math**

just plug in your numbers: v = pi/12 d^2 h
*May 5, 2016*

**MLZ**

3*2 = 6 but "3 times more than" is kind of fuzzy
*May 5, 2016*

**math**

subtract 1:45 + 2(1:12) + 0:45 from 4:15 pm
*May 5, 2016*

**Math**

42
*May 5, 2016*

**eh?**

no idea what that is supposed to mean
*May 5, 2016*

**Triangles**

I did it! What did you do?
*May 5, 2016*

**math**

d=c-s/n s/n = c-d s = n(c-d) If you meant d=(c-s)/n nd = c-s s = c-nd
*May 5, 2016*

**geometrt question**

f'(x) = -1/x^2, so at x=a, the slope is -1/a^2. So, now you have a point and a slope, so the line is y - 1/a = -1/a^2 (x-a)
*May 5, 2016*

**Calculus**

gee - you have the function. Plug and chug. s = πr√(r^2+h^2) ds = π(2r^2+h^2)/√(r^2+h^2) dr Now just plug in the numbers, using -0.1 as dr
*May 5, 2016*

**Physics, Math**

how long does it take to drop 4000 ft? use that time and 130 ft/s to get the distance needed.
*May 5, 2016*

**Functions**

(c) clearly g(x) is undefined for x=0 But, it is also undefined for x=1, because f is undefined there. g(1) = 1/(1-f(1)) Try that logic for h(x).
*May 4, 2016*

**math**

why the final "/1"? It does nothing. So, ignoring it Also, I don't see any initial subject. f maybe? and is that (√s)/c or √(s/c) ?
*May 4, 2016*

**Parametric Curve**

visit wolframalpha.com and type in your functions, as in (d) below http://www.wolframalpha.com/input/?i=parametric+plot+x%3D%282t+%2B+1%29sint,+y%3D%282t+%2B+1%29cost
*May 4, 2016*

**Math**

The following table shows the rate of water flow (in L/min) through a dam. t (min) 1 6 11 16 21 26 31 V'(t) (L/min) 1 8 2 9 7 5 9 Approximate the total volume of water that passed through the dam from t=1 to t=31 using Simpson's rule, with n=6.
*May 4, 2016*

**Math**

1/x --> 0 as x --> infinity so, what is cos(0)?
*May 4, 2016*

**algebra**

If you allow complex numbers, the two numbers are 2+√2i and 2-√2i
*May 4, 2016*

**Math**

363 = 300 * 1.21 = 300 * 1.1^2 so, each dimension is increased by 10%
*May 4, 2016*

**precalculus**

log(2+x)-log(x-3)=log2 log (2+x)/(x-3) = log 2 (2+x)/(x-3) = 2 2+x = 2x-6 x = 8
*May 4, 2016*

**st josephs**

420*1.055^4 + 520*1.055^3 + 750*1.055^2 + 540*1.055 = $2535.38
*May 4, 2016*

**Math**

looks good to me
*May 4, 2016*

**math**

7*4*h = 56
*May 4, 2016*

**Math**

looks like 3/5 to me oh, you mean 3/5 each? Then that would of course be 4 * 3/5 = 12/5
*May 4, 2016*

**Math**

Nope. It is 7!, but that's not 2520
*May 4, 2016*

**Math**

well, (3+7)/2 h = 25
*May 4, 2016*

**Algebra**

yes a^x where a is any constant is an exponential function
*May 4, 2016*

**Pre-Algebra**

you mean area, or length? If area, then (16+6w+2w)(48+6w+2w)-(16+6w)(48+6w) = 28w^2 + 128w in^2
*May 4, 2016*

**Algebra 2**

D = |2 3| |3 5| so B is out Replace the 1st column with (5,7) and that gives D.
*May 4, 2016*

**Algebra**

nope: add 10^3 * 10^5 = 10^8 what you have is 10*10*10 * 10*10*10*10*10 you multiply the numeric part 3*10^2 * 2*10^5 = 3*2 * 10^2*10^5 = 6*10^7
*May 4, 2016*

**Math**

all it tells me is that it is a parabola that crosses the x-axis at 4 and -2/5.
*May 4, 2016*

**math**

drama scale? You mean drawn to scale? 2(.005*6 + .005*13 + 6 * 13) = 156.19 m^2 I suspect a typo.
*May 4, 2016*

**Urgent help Ms sue**

i guess so
*May 4, 2016*

**Urgent help Ms sue**

how can the three designs be used to combat truancy in schools?
*May 4, 2016*

**Urgent help Ms sue**

Education researchers believe that a new approach to tackling truancy may help to reduce truancy levels. They wish to carry out a trial to compare the efficacy of the new approach with an existing approach. It is known that some schools have lower truancy rates than others, ...
*May 4, 2016*

**math**

no - it depends on where they started.
*May 4, 2016*

**math**

just change the sign of all the x-coordinates. try graphing and flipping a few points to see why this is.
*May 4, 2016*

**Math**

well, F=ma plug and chug. watch the units. Using clear English would also help...
*May 4, 2016*

**SAT math**

P(t) = 300,000
*May 4, 2016*

**algebra**

If you have x lbs of deluxe and y lbs of economy, then you want to maximize p=7x+5.4y subject to x/2 + y/2 <= 130 2x/3 + y/3 <= 170 now graph the lines and find the vertex with maximum p.
*May 4, 2016*

**huh?**

You want to try that in short clear sentences the way you got it? Don't make us figure out the question as well as the answers...
*May 4, 2016*

**Phy**

is the change linear? If so, then since 2.3 is 3/5 of the way from 2.0 to 2.5, the temperature would be 3/5 of the way from 0 to 100 degrees.
*May 4, 2016*

**Algebra 1**

.30(90-x) + 0(x) = .23(90)
*May 4, 2016*

**math**

Friday: the amounts are n and j Saturday: 2n/3 and j+n/3 Sunday: 2n/3 + (1/3)(j+n/3) and (2/3)(j+n/3) = j/3 + 7n/9 and 2j/3 + 2n/9 so, j/3 + 7n/9 = 96 2j/3 + 2n/9 = 120 Nathan had $54 and Jasper had $162 I'll let you verify the accuracy of the solution.
*May 4, 2016*

**math, functions**

g(x) = f(f) = 1/(1-f) = 1/(1-(1/(1-x)) = 1 - 1/x h(x) = f(g) = 1/(1-g) = 1/(1-(1 - 1/x)) = x But, as you say, watch for places where f is undefined. I'm sure you can figure those out.
*May 4, 2016*

**Algebra 1**

you want to decrease the concentration by 23/30, so that means you have to increase the volume by 30/23. 30/23 x = 90 x = 90 * 23/30 = 69 So, add 21 gallons of water
*May 4, 2016*

**DamotAk mathematecs**

x^2 = 90^2 + 90^2 - 2*90*90*cos(140°)
*May 4, 2016*

**Trig**

amplitude of 3/5: 3/5 cos(x) period of 3pi/2: 3/5 cos (4/3 x) y-intercept of 5: 22/5 + 3/5 cos (4/3 x) http://www.wolframalpha.com/input/?i=22%2F5+%2B+3%2F5+cos+%284%2F3+x%29
*May 3, 2016*

**Algebra**

so, the new tanks will hold (5/4)^3 as much oil, or 23437.5 gallons each
*May 3, 2016*

**Math**

Zoe feeds 6 horses per hour Matt feeds 2 horses per hour. So, together they feed 8 horses per hour, taking 4 hours to feed 32 horses
*May 3, 2016*

**Math**

40+10+25m = 50+15m+10m as given, if the Zumba class is each month, then both Gyms cost exactly the same: $50 in fees and $25 monthly
*May 3, 2016*

**geometry**

∠A = 15+15 = 30 = ∠B ∠C = ∠D = (360-30-30)/2 = 150 so, ∠ACD = 180-150-15 = 15 ∠BCA = 150-15 = 135
*May 3, 2016*

**PLEASE HELP ASAP**

looks good. when you say my answer is a? are you asking what your answer is?
*May 3, 2016*

**math**

since time = distance/speed, 24/(x-4) + 24/(x+4) = 14
*May 3, 2016*

**maths**

what is the coefficient of (x+2)^3 in the cubic taylor polynomial about -2 for the function f(x)= e^x?
*May 3, 2016*

**Geometry (check my work)**

why would you compare volume to surface area? The volumes are scoop: pi/6 * 6^3 = 113.1 cm^3 cone: pi/12 * 5^2 * 9 = 58.90 cm^3 the cone is too small, but because the volumes compare so.
*May 3, 2016*

**Maths Please help**

What is the quadratic Taylor polynomial about 2 for the function f(x)=square root x-1?
*May 3, 2016*

**maths**

surely you have the formula. What's the trouble? Just express it as a polynomial in (x + pi/3)
*May 3, 2016*

**maths**

What is the Linear Taylor polynomial aout -(pi/3) for the function f(x)=sin(x)?
*May 3, 2016*

**Maths ple**

b^8 is the 9th term, so its coefficient is 17C9 = 24310
*May 3, 2016*

**Maths ple**

what is the coefficient of a^9b^8 in the expansion of (a+b)^17
*May 3, 2016*

**Please help**

d=3, so there are 1+(260-2)/3 = 87 terms S87 = 87/2 (2+260) = 11,397
*May 3, 2016*

**Math**

L(L-3)=70 Hmmm. 10*7 = 70
*May 3, 2016*

**algebra PLEASE HELP ASAP**

looks good to me. 1 M in 7 letters.
*May 3, 2016*

**Math**

20 scores, with 5 less than 2.34 5 is 25% of 20, so the 25th %ile or 6 <= 2.34, making it the 30th %ile
*May 3, 2016*

**Algebra**

clearly you have skipped the definitions. arithmetic has terms which differ by the same amount geometric has terms with a common ratio, one to the next. a) has a ratio which changes: A(n) = A(n-1)*n A(n)/A(n-1) = n, which is not constant not GP or AP b)That +8 is a dead ...
*May 3, 2016*

**math**

do you have some kind of calculation to buttress your gut feeling? play with some numbers, at least.
*May 3, 2016*

**math**

original: n/d new: .5n/.75d = (2/3)(n/d) so, it is decreased by 33.3%
*May 3, 2016*

**Math -Trig**

for any x, cot(x) = 1/tan(x) 3pi/4 is in Quadrant II, so draw the triangle. x = -1 y = 1 cot(3pi/4) = x/y = -1/1 = -1 or, consider that cot(pi-x) = -cot(x) since cos(pi-x) = -cos(x) and sin(pi-x) = sin(x) so, cot(3pi/4) = cot(pi - pi/4) = -cot(pi/4)
*May 3, 2016*

**Math - Trig**

12 revolutions per minute 3.5*pi meters per revolution ...
*May 3, 2016*

**math**

Apparently greedy Ashley already had 1/4 of a pizza! anyway, 1 3/4 = 7/4 divide that by 11, as we're just talking about the friends.
*May 3, 2016*

**half-life**

.5mg is 1/8 of 4 mg 1/8 = (1/2)^3 so, that's 3 half-lives
*May 3, 2016*

**math**

60/36 ft * 12in/ft
*May 3, 2016*

**maths**

200 sin40
*May 3, 2016*

**Math**

1/6 of the time for each number.
*May 3, 2016*

**math**

11!/(2!2!2!2!) = 2,494,800
*May 3, 2016*

**Calculus**

see a nice calculator here to check your work: http://www.emathhelp.net/calculators/calculus-2/simpsons-rule-calculator/
*May 3, 2016*

**math**

(60 * 0.80 - 10) * 1.55 = $58.90
*May 3, 2016*

**math**

a = b + 0.50b = 1.5 b b = a/1.5 = 2/3 a so, b is 1/3 less than a, or 33.3% less
*May 3, 2016*

**math**

increasing by N% means the new value is 1+N/100 as much as the old value. So, we have new = old*(1+1)(1+1.5) = 5.00 * old so, old = new/5 or 20%
*May 3, 2016*

**math**

x * 1.25 = 2 x = 1.6 so, the first increase was 60%
*May 3, 2016*

**urgent math**

#1. 7^(9-3) = 7^6 NOT 7^(9/3) = 7^3 subtract exponents when dividing numbers. What you have is 7*7*7*7*7*7*7*7*7 ------------------------ 7*7*7 only three of the 7's cancel #2 z^8/z^12 = 1/z^4 = z^-4 So, D, not C #3 ok #4 not sure what ...
*May 3, 2016*