Tuesday
January 27, 2015

Posts by Steve


Total # Posts: 28,385

algebra
2.50(5/4) + 5.50(3/4) = x(5/4 + 3/4) x = $3.625
January 23, 2015

applied math
width is 10*12 = 120 inches So, it takes 120/4 widths Since the wall is an exact number of widths, we just need to figure the length to find the rolls. 10*12*4 = 480 in long so, we need 480/(20*12) = 2 rolls Makes sense, since each roll does 2 strips, and we need 4 strips.
January 23, 2015

algebra
I get 0.808
January 23, 2015

Math
P = (8,-3) The slope of PQ is ∆y/∆x = (3/(7-x)-(-3))/(x-8) = (3+3(7-x))/((7-x)(x-8)) = (24-3x)/((7-x)(x-8)) You have provided no data about Q or the desired slope, but just plug in the numbers you have.
January 23, 2015

math
using the two-point form of a line, you have (p-59) = (42-59)/(50-32) * (q-32) Now just rearrange that into p = 1/18 (1606-17q)
January 23, 2015

Algebra 1
You know two things: g+s = 425 g = s+25
January 23, 2015

college algebra
just solve for t in 16t^2 = 128
January 23, 2015

Math
you have a right triangle with legs 4 and 6. The hypotenuse is thus 2√13. I don't see any good choices.
January 23, 2015

math
you have the line intersecting when kx^2-5x+2 = -3x+4 kx^2-2x-2 = 0 Now recall the discriminant, d=b^2-4ac If d>0 there are two roots If d=0, there is one root If d<0 there are no real roots. The discriminant of your equation is 4+8k I expect you can determine when that ...
January 23, 2015

Math
if it takes t seconds to flip it once, then the actual flipping will take 10,000*t or 100,000*t seconds. There are 86,400 seconds in a day, if that helps.
January 23, 2015

math
a = 12 d = -6 T30 = a+29d so, . . .
January 23, 2015

math
I love it when you guys as us to show our work. Ever think of showing some of yours? y' = 6x+4 The line given has slope -2. So, when do we have 6x+4 = -2? x = -1 y(-1) = -2, so we want the point (1,-2) to be on the line. That means -2 = -2(-1)+b b = -4 See the graphs at ...
January 23, 2015

College Algebra
6400(1+.005/12)^(12*7) = $6627.92
January 23, 2015

Math
I'll do one, and you follow the steps for the other. 2cosx + √2 = 0 cosx = -√2/2 = -1/√2 x = π/4 on the unit circle, x = cosθ and y = sinθ, so the location is (-1/√2,1/√2) or (-1/√2,-1/√2) (QII or QIII) as usual, ...
January 23, 2015

integrated physics and chemistry
(12-20 m/s)/(32s) = -8/32 = -0.25 m/s^2 However, as the car was going north and slowed down, its acceleration was in the south direction.
January 23, 2015

maths
s = rθ you have r and θ, so plug them in (θ in radians). That will give you the actual arc length traveled. If you want the horizontal distance, assuming symmetry, then you will need x/2 = r sin(θ/2)
January 23, 2015

math
just equate the two: 2x^2-2x-3 = -x^2-2x-3 2x^2 = -x^2 x = 0 so, y = -3
January 23, 2015

math
clearly it is a geometric series, with a = 2 r = 3/7 So, use your summation formula for GP's: Sn = a(1-r^n)/(1-r) and plug in a and r.
January 23, 2015

Maths - eh?
No idea what xsq is. x^2? And what is the triple "xsq, ysq, z,sq" supposed to mean? I'll use © for the operator. You say (x,y,z)© = xsq, ysq, z,sq I have no idea what that means. Is it x^2+y^2+z^2? Gotta help me out here.
January 23, 2015

Cgs
x(t) = 9t - 1/3 t^3 + c since x(1)=2, 2 = 9 - 1/3 + c c = -20/3 x(t) = 9t - 1/3 t^3 - 20/3 when v=0, the particle has changed direction. That is when t=3. So, now just evaluate x(3).
January 23, 2015

Math
if you add the two equations, you get 5x = 20 I think you can solve that, eh?
January 23, 2015

Relative Extrema: AP Calculus
f = (3/4)x^4-x^3-3x^2+6x f' = 3x^3-3x^2-6x+6 f" = 9x^2-6x-6 extrema where f'=0 and f"≠0 f increasing where f' > 0 there are two inflection points because f" has two real roots.
January 22, 2015

Antiderivatives
Close, but no cigar. For powers, raise it by one and divide by it. So, F(x) = 1/6 x^6 -4(1/-2) x^-2 - 4x + c = 1/6 x^6 + 2x^-2 - 4x + c Since F(1) = 1, 1 = 1/6 + 2 - 4 + c c = 17/6 F(x) = 1/6 x^6 + 2x^-2 - 4x + 17/6 Frankly, I think the negative exponent is a typo, but that&#...
January 22, 2015

Math
You find out your faucet is leaking 10 pints of water every 3 hours. After 6 hours, how many gallons of water will have leaked from the faucet? How do I solve this problem?
January 22, 2015

Math
5-2*(6-(4+2))=5 Still thinkin' on the other one
January 22, 2015

help math algebra
for addition and subtraction, just collect terms with the same power (7a^5-a^3)-(a^5-5a^3-1) 7a^5-a^3-a^5+5a^3+1) (7-1)a^5 + (-1+5)a^3 + 1 4a^5 + 4a^3 + 1 When multiplying, use the distributive property (5x-3)(x^3-5x+2) (5x)(x^3-5x+2) - 3(x^3-5x+2) 5x^4-25x^2+10x-3x^3+15x-6 5x...
January 22, 2015

Math
1.50n + 2.00+1.25n
January 22, 2015

Math
standard form does not involve an intercept. The standard form for a line is Ax + By = C You have done it correctly. And, the intercept was given. It is zero.
January 22, 2015

geometry
has 5 sides of length 9 ft each
January 22, 2015

geometry
KL/JL = tan 24° you know KL, so now just solve for JL.
January 22, 2015

Algebra 1
Thank you
January 22, 2015

Algebra 1
Does the table represent an expoential function? x 1 2 3 4 y -1 -8 -27 -64 yes or no my answer is no
January 22, 2015

math
T5/T2 = r^3, so r^3 = (x^4/8)/(4x) = x^3/32 r = x/∛32 I suspect a typo, but we'll go with what we have. T10 = T5 r^5 = x^4/8 * x^5/(256∛2) = x^9/(2048∛2)
January 22, 2015

Math
It's good. You don't really need the leading "-" if you say a is negative, but having it there does signal your intentions clearly.
January 22, 2015

College Algebra
read the "trajectory" article at wikipedia.
January 22, 2015

Math
#1 is always true. Draw a triangle. Extend one side so that you can see the interior and exterior angles. They add up to a straight line (the extended side). Thus they are supplementary. #2 sometimes #3 never Have you tried drawing the triangles to illustrate the ideas?
January 22, 2015

hw dump
I've done a couple. How abut you show some work of your own, rather than just doing a homework dump?
January 22, 2015

math
2x+(3x-(4x-5))=x/4-2 2x+(3x-4x+5)=x/4-2 2x+(-x+5) = x/4 - 2 x+5 = x/4 - 2 3x/4 = -7 x = -28/3
January 22, 2015

math - bogus
x^2 + y^2 = 20 xy = 192(39.37^2) = 297600 Clearly x and y are less than 20. No way could their product be so huge. I suspect a typo.
January 22, 2015

math
The nth row has 35-4(n-1) = 39-4n plants. So, what is the largest multiple of 4 less than 39? Subtract that from 39. Or, just divide 39 by 4. The remainder is how many plants are in the last row. It is the row that is too short to subtract 4 from it again.
January 22, 2015

calculus
v(t) = ds/dt = 50-4t find t when v=0
January 22, 2015

math
.99(1.05)
January 22, 2015

Geometry
If the longer ladder is x, and reaches up y feet on the wall, then 8.3^2 + y^2 = x^2 8.3^2 + (y-9.1)^2 = (x-7.2)^2 x = 17.9
January 22, 2015

Geometry
a general circle is (x-h)^2 + (y-k)^2 = r^2 since the center is on y=2x+1, k=2h+1 (x-h)^2 + (y-2h-1)^2 = r^2 Since the circle passes through (4,5), (4-h)^2 + (5-2h-1)^2 = r^2 Since the circle is tangent to the y-axis, h=r, so (4-r)^2 + (4-2r)^2 = r^2 r = 2 or 4 You can now ...
January 22, 2015

Math-please help
If there are x seats at $5, then income = 5x + 9(500-x) expenses = 4000 profit = income - expenses
January 21, 2015

Math
Since c = 2pi r, r = c/2pi a = pi r^2 = pi(c/2pi)^2 = c^2/4pi so, plug in your value for c.
January 21, 2015

math
2/3 = 16/x x = 24
January 21, 2015

math
The ratio is clearly 24:5. So, QR:10 = 24:5 45:FG = 24:5
January 21, 2015

Math
94+67+83+93 = 337 5*90 = 450 Looks like she needed a 113 on the final test. I suspect a typo. Fix it and redo the math.
January 21, 2015

Math please help
(1/3 mi)/(1/15 hr) = 5 mi/hr (1/5 mi)/(1/30 hr) = 6 mi/hr I suspect you can finish it off from here, eh?
January 21, 2015

6th Grade Math
Either way is right, but it looks like you're both wrong 6 3/8 + 2 1/16 = 8 7/16 8 7/16 + 4 3/4 = 13 3/16 He should have added the mixed numbers on the right, then subtracted the sum: 4 3/4 + 2 1/16 = 6 13/16 So, 6 3/8 = t - 6 13/16 6 3/8 + 6 13/16 = 13 3/16 Guess you'...
January 21, 2015

Math
.85*.87 + .15*.85 = .867 Sounds right, since the final score is just about the same as the average so far.
January 21, 2015

Algebra 1
My answer is 4.5 x 10^9
January 21, 2015

Algebra 1
What is the correct simplification of 5.4x 10^12/ 1.2x 10^3 written in scientific notation?
January 21, 2015

math
N = kA/P If A is doubled, so in N. So, (D)
January 21, 2015

math
f(x) = 15 + 4.24(x/120)
January 21, 2015

Algebra 1
thank you
January 21, 2015

Algebra 1
clearly, it's 36(6x^5)
January 21, 2015

Algebra 1
A fraction reduces to 36. If it's denominator is 6x^5,what is it's numerator?
January 21, 2015

Math
4^.5x = (4^.5)^x = 2^x This is easy to see, since log_4(x^2) = 2log_4(x) = log_2(x)
January 21, 2015

Math
36:(36+28+16) = 36:80 = ?
January 21, 2015

precal
5r + 3(r+4) = 52
January 21, 2015

Physics
when they act in the same direction.
January 21, 2015

math
it will travel 1km in 1km. If it takes 1000 hops, it will travel 2km It will take 500 hops to travel 1km.
January 21, 2015

math
(-2,12)
January 21, 2015

Algebra II
I don't think you really want a "z" floating around. I'll assume you meant a "2". The first two are just straightforward multiplication and division. You can surely do those. (g◦(h◦f))(-4) = g(h(f(-4)) = g(h(-2)) = g(9) = -33
January 20, 2015

Calculus: Intergration
This kind of stuff usually works best with a trig substitution. Note that 4x-x^2 = 4-(x-2)^2 So, let u = x-2 and you have du/(4-u^2)^(3/2) Now, let u = 2sinθ du = 2cosθ dθ 4-u^2 = 4-4sin^2θ = 4cos^2θ Now the integrand is 2cosθ dθ/8cos^3θ...
January 20, 2015

Trig/Precalc #1
If we call the two circles C1 and C2, respectively, then note that (2,1) lies on C2. So, the external tangents will be bisected by the line joining the two centers. Note that both circles are tangent to the x-axis. So, figure the slope of the line joining the two centers, and ...
January 20, 2015

Pre-Calc
This is just algebra I. You want x where -76x^3+4830x^2-320000 = 800000 I suggest a graphing utility, as this has no rational roots.
January 20, 2015

Pre-Calc
the circumference of the circle is 100-x. So, the area is a = (x/4)^2 + π((100-x)/2π)^2 This is just a parabola, so its vertex (minimum area) is easy to find. For the maximum area, compare a at the ends of the domain.
January 20, 2015

Math
2:3 = 18:x so, x=27, the no. of blue pens. Now, you have to decide the color(s) of the 3 pens removed to figure the new ratio.
January 20, 2015

Pre-Calc
the page is clearly 4" wider and higher than the print. That means that (x-4)(y-4) = 30 y-4 = 30/(x-4) y = 4+30/(x-4) The area A is xy, so A = x(4+30/(x-4)) = x(4(x-4)+30)/(x-4) = x(4x-16+30)/(x-4) = 2x(2x+7)/(x-4) I think the rest is fairly straightforward
January 20, 2015

Math
Piece of paper is 0.0075 inch thick. How many sheets of paper will be in a stack that is 2.25 inches high?
January 20, 2015

Math
Please help!!!!!!!!!!!!!
January 20, 2015

Math
First week sells 6 chairs for $80 each. Next week, if chair is not sold, it will sell for 0.85 times previous week's price. Store needs to sell 6 chairs for total of $270 to make a profit. what is the last week in which all 6 chairs could be sold so that the store makes a ...
January 20, 2015

Science
s = vt - 1/2 at^2 20t - 1/2 at^2 = 100 Also, v = Vo-at, so 20-at = 0 at = 20 so, 20t - 1/2(20)t = 100 t=10 So, a = 2 F = ma = 800*2 = 1600N
January 20, 2015

Coll Algebra
If the short side is x, then x + 2x + 2x = 30
January 20, 2015

Math
In a way. To say that the single equation on the left is the "same" as the two other equations is not technically true, but it does have the same solutions as the others. Actually, there is no value of x such that x=0 and x+6=0. x(x+6) = 0 is true if x=0 OR if x+6=0...
January 20, 2015

physics
F = ma You have m and a.
January 20, 2015

algebra
add the exponents of all the variables in each term. The degrees can be easily seen to be 4, 5, 5, 0 The degree of the polynomial is the highest degree among the terms. In this case, 5.
January 20, 2015

Math
No. In 1 minute, 1/20 of the tub fills, while 1/15 drains. So, the net rate of filling is 1/20 - 1/15 = -1/60 So, in 60 minutes the full tub drains. This assumes, of course, that the drain is opened when the tub is completely full.
January 20, 2015

Math-Polynomials/Zeros
if you're talking about quadratics with no constant term, then they look like y = ax^2+bx That's just y = x(ax+b) and it has two real roots (0 and -b/a). No complex roots are possible.
January 20, 2015

Math
what, no ideas? Check the discriminant. ax^2+bx+c has only complex roots if b^2-4ac < 0
January 19, 2015

Math
I gotta think you meant f(x) = x^4-4x^2+k we know that x^4-4x^2 = x^2(x^2-4) = x^2(x-2)(x+2) so it has 3 real roots, one repeated. x^4-4x^2+4 = (x^2-4)^2 = (x-2)^2(x+2)^2 so it has 4 real roots (2 distinct) x^4-4x^2+k has 4 distinct real roots if 0 < k < 4 x^4-4x^2+k has...
January 19, 2015

math
incorrect. |x| is never negative.
January 19, 2015

Math
f(x) = (x-1)(x-3) So, the vertex is at x=2. The restriction on the domain ensures that we only have the left branch of the parabola, so f is 1-to-1 and will have an inverse. x = y^2-4y+3 x = (y-2)^2 - 1 x+1 = (y-2)^2 y-2 = ±√(x+1) we only want the left branch, so ...
January 19, 2015

math
I assume "this region" means the green, less the hole. Since the area of a circle is pi r^2, just subtract the small area from the large area.
January 19, 2015

Math
1/20 - 1/15 = -1/60 So, 1/60 of the tub drains every minute. . . .
January 19, 2015

Math
f(x)=x^2+3x+2/x+1 = (x+1)(x+2)/(x+1) does not have a vertical asymptote. It just has a hole at x = -1 We want something with (x-3) on top, and (x+1) in the bottom, so f(x) = (x-3)/(x+1) has the zero and the vertical asymptote. Note that for large x, f(x) -> 1. So, we can ...
January 19, 2015

Geometry
42
January 19, 2015

calc
nope. Just as d/dx x^n = n x^(n-1) ∫n x^(n-1) dx = x^n or, as it is ually written, ∫x^n dx = 1/(n+1) x^(n+1) So, ∫x^(1/2) dx = 2/3 x^(3/2) see when you take the derivative of that, that you get x^(1/2)
January 19, 2015

calc
just expand the expression (3+x)x^(1/2) = 3x^(1/2) + x^(3/2) then just use the power rule on each term.
January 19, 2015

ap calc
yes. so you are left with just (x^2-4) as usual, (√x)^2 = √(x^2) = x
January 19, 2015

Algebra
terms are separated by + or - signs just add exponents of all the factors. The degrees of the terms are thus easily seen to be 4,5,5,0
January 19, 2015

arithmetic
First, balance parens and brackets: 0.2[5.28-(0.7)] 0.2[5.28-0.7] 0.2[4.58] 0.916 Or, you can distribute the multiplication: 0.2[5.28-(0.7)] 0.2(5.28) - 0.2(0.7) 1.056 - 0.14 0.916
January 19, 2015

math
3 - 5 = -2 -2 is not in N
January 19, 2015

calculus
(If the base has side x and the box has height h, the area 2x^2 + 4xh = 600, h = (300-x^2)/2x So, the volume v = x^2 h = 150x - x^3/2 dv/dx = 150 - 3/2 x^2 So, dv/dx=0 when x^2 = 100 I think you can take it from there, ok?
January 19, 2015

math
just start writing down the facts as math. n = 2d+2 eight fewer quarters than twice the number of nickels q = 2n-8 value of the quarters was $1.60 more than four times the value of the nickels and dimes together 25q = 4(10d+5n)+160 Putting all that together, we have n = 2d+2 q...
January 19, 2015

AP Calc
well, it's clear that f(x) = x^2-3x+c and you know that f(2) = 5, so just find c.
January 19, 2015

Geometery
you just have to remember that the angles of a triangle add up to 180 degrees. So, with angles M+P+N = 180 x + 2x-1 + 2x+1 = 180 Now it's easy to find x, the evaluate the actual angle measures.
January 19, 2015

Pages: <<Prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>

Members