Monday

November 30, 2015
Total # Posts: 35,847

**maths**

the inside volume is 48*48*36 The outside volume is 49*49*36 subtract to find the wood.
*November 7, 2015*

**Calculus**

we have x^2+y^2 = 15^2 x dx/dt + y dy/dt = 0 Let x be decreasing, and y increasing. Then when y=9, x=12, and we have 12 dx/dt + 9*4 = 0 dx/dt = -3
*November 7, 2015*

**Calculus**

so, I guess the real(!) answer is indeed that there is no absolute max value.
*November 7, 2015*

**Calculus**

on the given domain, f(x) = x^2-4x+7 minimum is f(2)=3 limit as x->0 of f(x) = 7 f(3) = 4 So, abs min = -9 abs max = 7 not strictly true, since f(0) is undefined, and there is no maximum number less than 7. See the graph at
*November 7, 2015*

**math**

10000/8300 = 1.205 So, n(t) = 8300 * 1.205^n
*November 6, 2015*

**Help Please, Oh Please--Algebra**

terms are separated by + or - signs. So, there are 3 terms, making this a trinomial.
*November 6, 2015*

**math**

0.5^(t/5730) = 0.7 t/5730 * log .5 = log .7 t/5730 = 0.5145 t = 2949
*November 6, 2015*

**computers**

void read your manual much?
*November 6, 2015*

**ALGERBRA 2!!!**

the point-slope form of the line is y+6 = -5(x-2) which ones (possibly rearranged) match that?
*November 6, 2015*

**calculus**

I assume that you mean ∫ (1+xe^x)/x dx = ∫ 1/x + e^x dx That should get you going.
*November 6, 2015*

**Calculus**

you know that 1/n^p converges for p>1. Loosely, (n+5)/((n^7+n^2)^(1/3)) < (n+5)/n^(7/3) < (n+5)/n^2.33 < 1/n^1.33 so it converges
*November 6, 2015*

**calculus**

∫ 9tanx cosx+5 dx = ∫ 9sinx + 5 dx ...
*November 6, 2015*

**MATH**

consider factorials: 6 = 3! 24 = 4! ... 720 = 6!
*November 6, 2015*

**Maths**

first, get rid of those pesky fractions and you have x+3y = 2 2x+3y = 6 now subtract the 1st from the 2nd and you have x = 4 Then plug that into either equation to find y: 4+3y = 2 y = -2/3 final step: check those values in each of the original equations to make sure you have ...
*November 6, 2015*

**Algebra**

250/22 * $2.40 doesn't matter how much it costs to fill your tank. It only matters how much a gallon of gas costs.
*November 6, 2015*

**math**

google and wikipedia are your friends. Use them.
*November 6, 2015*

**Math**

well, how many times do they intersect on [0,2π]? Then they intersect 2012/2π times that many times on the larger interval.
*November 6, 2015*

**bussness math**

200 * 0.05/12
*November 6, 2015*

**polynomial/synthetic or long division**

a little synthetic division quickly shows that x^3+6x^2+11x+6 = (x+1)(x^2+5x+6) = (x+1)(x+2)(x+3)
*November 6, 2015*

**Math**

4*12 * $3
*November 6, 2015*

**math**

2/7 x = 6 2x = 42 x = 21 or, you could say, if 2/7 is 6, 1/7 is 3 so, the number is 21
*November 6, 2015*

**Geometry**

since I have no diagram to see, I cannot confirm nor refute your assertion.
*November 6, 2015*

**bluehills high school**

cos(90) = 0, so you cannot divide by it. I suspect a typo, especially since there is no equation to solve.
*November 6, 2015*

**math**

n = (33-15)/2
*November 6, 2015*

**calculus**

f = x ln(x/5) f' = 1 + ln(x/5) critical points where f'=0, so 1 + ln(x/5) = 0 x = 5/e f(5/e) = -5/e now, checking the endpoints of the interval f(1/10) = -ln(50)/10 f(5) = 0 So, looks like the min is -5/e, max is 0.
*November 6, 2015*

**Calculus**

f = x e^(-x/2) f' = (2-x) e^(-x/2) critical points where f'=0, so that's at x=2. f(2) = 2/e check the endpoints of the interval for absolute min.
*November 6, 2015*

**math**

c = 2a c+a=1200
*November 6, 2015*

**math's**

12550(1.045)^5 - 1)
*November 6, 2015*

**Calculus**

first off, get rid of the 4x. Let u = 4x du = 4dx then we have 1/4 ∫ cot^3 u du = 1/4 ∫ cot u cot^2 u = 1/4 ∫ cot u (csc^2 u - 1) du = 1/4 ∫ cot u csc^2 u du - 1/4 ∫ cot u du = -1/8 cot^2 u - 1/4 log(sin u) + C = -1/8 cot^2(4x) - 1/4 log(sin(4x)) + C
*November 5, 2015*

**GNC Sirsa**

(1,2,1)
*November 5, 2015*

**Math**

sounds like your number is 4k+4
*November 5, 2015*

**math**

or, consider that the walker covers 1/4 mile while the runner covers 3/4 mile. (1/4 mi)/(3 mi/hr) = 1/12 hr = 5 min.
*November 5, 2015*

**Geometry**

well, it sounds like it has been rotated 3 places to the left.
*November 5, 2015*

**Math**

h = n-5
*November 5, 2015*

**Math grade 12**

note that 5π/12 = 2π/3 - π/4 Now just use your difference formula for cos(a-b) and take the reciprocal for sec(x)
*November 5, 2015*

**Math**

nope. 400m head start. Bob runs 800 m while Jim runs 1200 m. 3 is 50% more than 2. 2 is not 50% less than 3.
*November 5, 2015*

**college algebra**

$15k is half of $30k, so you want t years, where 0.9^t = 0.5
*November 5, 2015*

**Math**

No, a 600m head start would mean that Jim runs twice as fast as Bob. Jim runs 3m while Bob runs 2m. So, when Jim has run 1200m, Bob has only run 800m. So, give Bob a 400m head start. Doesn't seem like Jim is getting a fair deal, though ...
*November 5, 2015*

**math**

you can't be sure, but you do need to know the general shape of all exponential curves.
*November 5, 2015*

**math**

first, find out the dimensions of the Constitution.
*November 5, 2015*

**Calculus**

y = x^2+2 y' = 2x So, at (h,k) y'(h) = 2h So, you want a line with slope -1/(2h) passing through (0,3) y-3 = -1/(2h) x h^2+2 - 3 = -1/2 h^2 = 1/2 h = 1/√2 so, (1/√2,5/2) is closest to (0,3) 1/2 + Or, consider the distance formula. We have z^2 = (x-0)^2 + (y...
*November 5, 2015*

**calculus**

If she lands a distance x downstream, then she swims √(3.7^2+x^2) runs 7.4-x So, the time taken is t(x) = √(3.7^2+x^2)/7.4 + (7.4-x)/14.8 find x where dt/dx=0 I get x = 3.7/√3 All these speeds and distances are creepily multiples of 3.7
*November 5, 2015*

**Algebra**

well, just divide. You will see that (x+3) divides it evenly, and the quotient is -2x^2+5x-2) so, F(x) = -(x+2)(2x^2-5x+2) = -(x+3)(x-2)(2x-1) The zeros can now just be read off.
*November 5, 2015*

**Please Help!!! Algebra...**

Urn 1: 6 blue of 10 total Urn 2: 2 blue of 8 total So, P(blue,blue) = 6/10 * 2/8
*November 5, 2015*

**Precal**

#14. well, e^0 = 1, so N(0) = 10000/1250 #15. Just plug in 1 or 5 for t and crank it out. #16 just solve for t in 10,000/(5 + 1245e-.97t) = 1000 5 + 1245e-.97t = 10 1245e^-.97t = 5 e^-.97t = 5/1245 -.97t = ln(5/1245) = -5.517 t = 5.68 days
*November 5, 2015*

**math**

clearly the runner travels 3/4 mile and the walker 1/4 mile. So, how long does it take? (1/4 mi)/(3 mi/hr) = 1/12 hr = 5 min.
*November 5, 2015*

**Pre-Algebra**

1/2 * 1/2 * 5/26
*November 5, 2015*

**Geometry**

so would it be 2,-3 or 2,5
*November 5, 2015*

**Geometry**

(x,y) -> (x+5,y) -> (x+5,1-(y-1)) = (x+5,2-y) So, plug in your numbers
*November 5, 2015*

**Geometry**

a>p=a'(-3,-3) for the glide reflection where the translation is (x,y)>(x+5,y) and the line of reflection is y=1. What are the coordinates of a'?
*November 5, 2015*

**MATH**

√3*√21 = √3*√3*√7 = 3√7
*November 5, 2015*

**Geometry**

p>p'(-2,-6) for the glide reflection where the translation is (x,y)>(x,y-1) and the line of reflection is x=1. What are the coordinates ofP?
*November 5, 2015*

**MATH**

the center of the pyramid is 115m from each edge. Find the height h using h/115 = tan51°50' Now figure the slant height s, using s^2 = 115^2+h^2 The isosceles triangles thus have base 230 and altitude s. The edges of the pyramid(the equal sides of the triangles) have ...
*November 5, 2015*

**COLLEGE ALGEBRA**

If the corral has dimensions x and y, with the barn as a part of side y, then 2x+2y-20 = 320 There are lots of values for x and y that fit that requirement. If y is the long side, then we just need x+y=150, so any value of y between 75 and 150 will work fine, but some of the ...
*November 5, 2015*

**Geometry**

If you consider black and white the same, then the symbol is symmetric about its center.
*November 5, 2015*

**Geometry**

thank you I'll take that as a no
*November 5, 2015*

**Geometry**

durr
*November 5, 2015*

**Geometry**

what type of symmetry does the ying yang symbol have? I don't think it has symmetry
*November 5, 2015*

**Geometry**

Which letter has rotational symmetry? I J K L IMy answer is I
*November 5, 2015*

**Calculus**

see related questions below.
*November 5, 2015*

**Geometry**

my pleasure, Steve
*November 5, 2015*

**Geometry**

different steves Thank you Steve
*November 5, 2015*

**Geometry**

looks good to me.
*November 5, 2015*

**Geometry**

The vertices of a triangle are P(-4,1), Q(-2,-8), R(8,-1). What are the vertices of the image reflected across the y-axis? my answer is P'(4,1),Q'(2,-8),R'(-8,-1)
*November 5, 2015*

**Geometry**

thank you
*November 5, 2015*

**Geometry**

right on
*November 5, 2015*

**Geometry**

Which rule describes the transformation that is a reflection across the x-axis? a- (x,y)>(x,-y) b- >(-x,y) c_ >(-x,-y) d- >(y,x) my answer is a
*November 5, 2015*

**math**

review your basic rules in this stuff. f = x^2/(x^2-1) f' = -2x/(x^2-1)^2 f" = 2(3x^2+1)/(x^2-1)^3 I expect you can find intercepts ok. Since f(x) is even, it's symmetric about the y-axis. vertical asymptotes where x^2-1 = 0 Since f = 1 + 1/(2(x^2-1)) horizontal ...
*November 5, 2015*

**Calculus**

in inches, v = (36-2x)(48-2x)x dv/dx = 12(x^2-28x+144) dv/dx=0 when x = 6.789" ≈ 0.5657 ft For (b), just plug in k, and you have v = x(k-2x)^2 dv/dx = 12x^2 - 8kx + k^2 dv/dx=0 when x = k(2±√3)/6 The max will occur at x = k(2-√3)/6, since (2+&#...
*November 5, 2015*

**quantitative reasoning**

needs x where x(1+.0725/4)^(4*5) = 16000
*November 5, 2015*

**Calculus 1-Optimization**

the volume v = x^2 z = 4000, so z = 4000/x^2 the area is a = x^2 + 4xz = x^2 + 16000/x da/dx = 2x - 16000/x^2 da/dx=0 when 2x - 16000/x^2 = 0 x^3 = 8000 x = 20 So the box is 20x20x10 cm
*November 5, 2015*

**Calculus 1 optimization**

That is correct. Good job. As usual in problems like this, maximum area or minimum fencing is achieved when the total fence is divided equally between lengths and widths.
*November 5, 2015*

**Mathematics**

The number n = 552k+53 = (23*24)k + 23*2 + 7 n/23 = 24k+2 R 7 Hmmm.
*November 5, 2015*

**programming ( qbasic)**

google is your friend. Use it. http://www.schoolfreeware.com/QBasic_Tutorial_38_-_Making_A_Function_-_QB64.html
*November 5, 2015*

**probability**

(a) p = 8/15 * 7/14 * 6/13 This is like choosing items without replacement, right?
*November 5, 2015*

**Calculus**

You are correct. It's just that at x=11, the linear approximation isn't very good when you get var away from 11. You were not asked to get an approximation which agrees with the true value to 3 places, just to get a value out that far. Extra credit: how far away from ...
*November 4, 2015*

**Pre algebra**

The first 7 are spot on. 8-10 you don't show.
*November 4, 2015*

**geometry**

the angles sum to 180. So, if the base is x, each of the other two sides is 2x-3. SO, now you have to find x when x + 2x-3 + 2x-3 = 44 Having found x, you can now determine the lengths of the sides.
*November 4, 2015*

**math**

well, just find the two derivatives: dR/dq = 600-2q dC/dq = 50 so, you want 600-2q = 50 q = 275 Note that this is the value of q at the vertex of the parabola, q = -b/2a = -550/-2. Note the typo in your final function. Should be +550q, not -550q
*November 4, 2015*

**Calculus**

see related questions below
*November 4, 2015*

**Calc**

see related questions below
*November 4, 2015*

**Porportions (Pre-Algerbra)**

clearly not C, since 12/36 = 1/3 12 is about 1/2 of 22, so you' expect the answer to be about half of 55. So, not 45. In fact, doing the actual math 22/55 = 12/H 22H = 12*55 H = 12*55/22 = (2*6*11*5)/(2*11) = 6*5 = 30 6/11 = 84/x 6x = 11*84 x = 154
*November 4, 2015*

**science**

how long does it take to fall 10m? Then, using that value of t, solve for v in vt = 3 since the ball must travel horizontally for 3m in that amount of time.
*November 4, 2015*

**Calculus**

So, why is ∞ not a valid answer? Sometimes that is the limit. lHospital does not guarantee that the limit is defined. It just allows one to make sure that an indeterminate form is avoided. 1/0 is not indeterminate -- it is infinite. The only thing that bothers me is that...
*November 4, 2015*

**Precal**

fractions are just numbers. Why is it any easier to find θ if cosθ = 4/25 ?? You still have to evaluate cos^-1(x) using your calculator. Seems to me that using a decimal is even easier than using fractions. Now, if you have some problem like sin(arccos(.16)) then it ...
*November 4, 2015*

**Math**

Your alternate answer of 112° is not possible, since then 12 would not be the longest side. 68° is the only right choice. rather than saying 2nd function sin try saying sin^-1(.93) or arcsin(.93) calculator buttons vary from model to model. We are talking math here, ...
*November 4, 2015*

**Math**

You have weird notation. Using ^ for exponents, 3^2^3 = 3^8 so I guess (A)
*November 4, 2015*

**Math**

Looks good to me.
*November 4, 2015*

**math**

well, since T5-T1 = 4d, d=3/2 we know a=3, so Sn = n/2 (2*3+(n-1)(3/2)) 3/4 (n^2+3n) = 81 n^2+3n-108 = 0 (n+12)(n-9) = 0 n=9 and the sequence is 3 4.5 6 7.5 9 10.5 12 13.5 15 The sum is 81
*November 4, 2015*

**Calculus**

If the width is w, the length is 250000/w, so the perimeter is p = 2w + 250000/w dp/dw = 2 - 250000/w^2 dp/dw=0 when w = 500/√2 = 353.6 ft So, the least fencing needed is 1414.2 ft
*November 4, 2015*

**Math**

Just collect like terms (same radical): 5√7 + 12√6 - 10√7 - 5√6 Should be easy now, right? Can you simplify 5x+12y-10x-5y? Same idea here.
*November 4, 2015*

**maths**

If the sun is behind the building, and the building's height is h, then the longest shadow (s) cast by the fence is when the sun is just about to go down behind the building. s/3 = (s+10)/h If the sun is not directly behind the building, then all bets are off.
*November 4, 2015*

**trigonometry - oops**

rats - 1/2 * 250h = 43560 so, h=348.8 Adjust the other calculations accordingly. Good exercise for the student :-)
*November 4, 2015*

**trigonometry**

Draw a diagram. Let the 1-acre parcel be triangle ABC, with B=85° AB = 250 h is the altitude from AB to C x is the length of side BC y is side AC 250h = 43560 h = 174.24 h/x = sin85° x = 174.91 y^2 = 250^2 + x^2 - 500x cos85° y=292.36 x/sinθ = y/sin85° sin...
*November 4, 2015*

**maths**

cost: 20000 revenue: 10000*1.10 + 10000*0.90 = 20000
*November 4, 2015*

**Mathematics**

The numbers are x, x+1, x+2. So, x + 3(x+1) = 5(x+2)-18
*November 4, 2015*

**Trigonometry**

using the law of sines, the pole's height h can be found after determining all the angles involved. h/sin51° = 47/sin47°
*November 4, 2015*

**trigo**

draw a diagram. extend the chimney downward to where it meets a horizontal line drawn from the point Q 10'8" down the roof. Label T = top of chimney B = bottom of chimney PQ = base of right triangle TPQ. using the law of sines, 6/sin17°40' = 10'8"/...
*November 4, 2015*

**Calculus I**

Why thanks, young fan... But seriously though, i'm just here to help Mjeed in his homework so, yeah have a nice day gentlemen :)
*November 4, 2015*

**Calculus I**

f = x - arctan(x) f' = 1 - 1/(1+x^2) = x^2/(1+x^2) f'=0 only at x=0 f" = 2x/(1+x^2)^2 f"(0) = 0, so x=0 is not a min or a max, but a point of inflection. See the graph at http://www.wolframalpha.com/input/?i=x+-+arctan%28x%29
*November 4, 2015*