Saturday
December 10, 2016

Posts by Steve

Total # Posts: 47,042

math
it dropped 6K in 2 years. That's 3K per year. So, it started at 3K more than 20K. y = 23000 - 3000x
October 22, 2016

Algebra
5646000 * 1.047^n = 13000000000
October 22, 2016

Algebra
$15/hr
October 22, 2016

Algebra
do you not see the relation between hours and money?
October 22, 2016

Math, Functions
the domain of all polynomials is (-∞,∞) There is no value of x which is not allowed. Since the graph is a sloping straight line, it extends forever in both directions, so the range is also (-∞,∞)
October 22, 2016

Math - correction
nope. only 13 are boys. 22:13
October 22, 2016

Math
counting boxes, with x sold on Monday, x + x-3 = 15 12x is the number of pencils.
October 22, 2016

math
the lot will be 37.5 by 25 where the extra piece is parallel to the short sides.
October 22, 2016

math
the monthly charge for A is clearly 14.45 (0 minutes) So, for B, $(22.10-14.45)/45min = $0.17/min
October 21, 2016

Algebra
yes
October 21, 2016

Math
just multiply by 45 512.
October 21, 2016

Math
56000+9x = 16x
October 21, 2016

calculus
M'(x) = .0009x^2 - .132x + 4.64 Now just evaluate M' for your years.
October 21, 2016

Algebra
A is correct B is correct if the line goes through (-4,0)
October 21, 2016

Math
fix typo revenue = p*demand then take derivative.
October 21, 2016

Calculus
for f"=0 you need sin2x - cos4x = 0 sin2x - (1 - 2sin^2(2x)) = 0 2sin^2(2x) - sin(2x) + 1 = 9 (2sin2x+1)(sin2x-1) = 0 sin2x = -1/2 sin2x = 1 Count the solutions in the interval. Looks like ten to me.
October 21, 2016

physics
use the Pythagorean Theorem, since the directions are perpendicular.
October 21, 2016

Maths
45-(30+20-8) = 3
October 21, 2016

math
well, a*10^5 = 2000
October 21, 2016

math
(-28.9-(-79.9))/(19.125-12.75-(79.9/18.8)) = 24.0 ft/min
October 21, 2016

Calvary School
9/4 yards, 3 inches
October 20, 2016

Physics
8*10 + 2(-5) = (8+2)v
October 20, 2016

algebra/AP physcis
Can't be done. If you move the 1.2v^2/.6 to the left, you wind up with -.2v^2/.6 = 9.8 The left side is negative and the right side is positive. I suspect a typo somewhere, or an error in devising the equation.
October 20, 2016

Calculus
y = (x^2 +2x)^3(x+2) = x^3(x+2)^4 y' = 3x^2 (x+2)^4 + x^3 * 4(x+2)^3 * 1 = x^2(x+2)^3 (3(x+2) + 4x) = x^2(x+2)^3(7x+6)
October 20, 2016

Math
if p>0, then q<0 and -3p+4q is negative. So, p<0 and q>0 -3p > 0 4q > 0 so -3p+4q > 0
October 20, 2016

Math
huh?
October 20, 2016

GCF
940 = 20*47 420 = 20*21 940-420 = 20(47-21) = 20*26 = 520
October 20, 2016

math
f(g) = 4g-5 = 4(3x)-5 = 12x-5
October 20, 2016

Math
sides have ratio 36/22 areas have ratio (36/22)^2
October 20, 2016

MATH
x(t) = -t + t^3/6 v(t) = dx/dt = -1 + t^2/2 I think you can now answer the questions if you think a bit.
October 20, 2016

Math
well, the triangle's 3 sides can each intersect with two sides of the rectangle, making six intersections. Now see what you can do with the circle.
October 20, 2016

Algebra
3.29, naturally. cost = 3.29 * gals
October 20, 2016

pre-calc
Do you mean e^-t cost + e^-t sint = 0? If so, factor out the e^-t and you have e^-t (cost - sint) = 0 e^-t is never 0, so that leaves sint = cost or tant = 1 I think you can work with that, eh? Remember all four quadrants.
October 20, 2016

algebra 1
looks something like y = 2^x but you will have to adjust it a bit.
October 20, 2016

Math
nope. You lost a minus sign.
October 20, 2016

Math
1/3 Divided by 3 = 1/9 or 0.11111...
October 20, 2016

Math
1/3 Divided by 3
October 20, 2016

physics need asap help
add up the momentum vectors. Assuming the particles are moving in the +x and +y directions before the collision, with speeds u and v, <mu,0> + <0,2mv> = <3m*2sin37°,3m*2cos37°> now just solve for u and v.
October 20, 2016

Math
common ratios, common ratios... Find one ratio and use it to get the other dimension.
October 20, 2016

Math
the ratio of heights is the same as the ratio of ground distances, namely 25/10
October 20, 2016

Math
2/4 divided by 6
October 20, 2016

A.P.
Good question. If so, then the common difference must be zero, so x-2 = 5 x = 7 and the terms are 5,5,5 However, if the last terms is supposed to be x+2, then the terms are clearly 3,5,7
October 20, 2016

math
tell you what -- I'll show you one. Then you can work on the second. 6 dimes = 6*10 = 60 Now just replace some of the dimes with nickels.
October 20, 2016

Check my answers
Yes Ms. Sue
October 20, 2016

Check my answers
100% Correct for the Practice
October 20, 2016

Check my answers
1. B 2. B 3. C 4. D 5. B 6. A 7. B 8. A, C 9. A 10. C 11. C 12. A 13. D 14. A 15. C
October 20, 2016

Check my answers
I will check you answers give me a minute.
October 20, 2016

maths sequence
Recall that the sum of n terms is Sn = n/2 (first+last)
October 20, 2016

Social Studies
I think B. What do you think?
October 20, 2016

Algebra
Not quite sure what you means by "3/x 1/9" If I use conventional online notation, I could write something similar as 1/3 + 3/x - 9/x^2 = (x^2+3x-9)/x^2 Those do not simplify easily, so I expect I have gotten something wrong. Maybe you could clean it up a bit and ...
October 20, 2016

math
Or, since the two numeric terms have a ratio of r^2, so r^2 = 75/12 = 25/4
October 20, 2016

algebra 2
(c) obviously the vertex form (d) standard form, so you have the needed a,b,c coefficients. What do you think for (a) and (b)? Try doing them and see what happens.
October 20, 2016

Math (Function differentiable)
for the function to be continuous, the limit on both sides must be the same. They are both 5 (not 4!). So, your function is continuous. But that is not enough. Think of f(x) = |x|. It is continuous, but not differentiable at x=0. For it to be differentiable, the derivative on ...
October 20, 2016

physics
conserve momentum: Is the ball stationary, moving directly away/toward him? Pick your answer, and then just write the momentum equations before and after collision. Solve for v.
October 20, 2016

Algebra 2
no graph
October 20, 2016

Algebra
-4 <= 4(6y-12)-2y -4 <= 24y - 48 - 2y -4 <= 22y - 48 . . .
October 20, 2016

Calculus
revenue = price * demand If there are x price decreases, then price: p(x) = 5.00 - .20x demand: d(x) = 200 + 5x so, x = (d-200)/5 r(x) = p(x)*d(x) = (5 - x/5)(200+5x) = (5 - (d-200)/25)d = 13d - d^2/25 marginal revenue for demand is thus dr/dd = 13 - 2d/25 r'(120) = 13 - ...
October 20, 2016

Math
1/t + 1/(3t) = 1/9
October 20, 2016

math
so far, it's a tie!
October 20, 2016

Algebra
well, 1/5 + 2/5 = 3/5 4/5 - 1/5 = 3/5 so, (3/5)(x+y) hah!
October 20, 2016

coordinate geometry
Is that y = (√3)x+4 ? The other circle is clearly (x+2)^2 + (y+2)^2 = 4 and the way the question is worded, it appears that the first circle is also tangent to the x-axis at (1,0), making it (x-1)^2 + (y-k)^2 = k^2 Now it should not be too hard to find k so that the ...
October 20, 2016

Math
this is (almost) correct, since sec^2/tan^2 = 1/cos^2 * cos^2/sin^2 = csc^2 Actually, the derivative is -csc^2x cotx = cosx/sinx d/dx(cotx) = (-sinx*sinx - cosx*cosx)/sin^2x = -(sin^2x-cos^2x)/sin^2x = -1/sin^2x = -csc^2x Next time, show your work, so we can see what went wrong.
October 20, 2016

Maths
what's the trouble? Just write all that as math: (3/4)x + 3 1/2 = 6 1/2 - (2/3)x Now just solve for x.
October 20, 2016

Trigonometry
First, review your basic trig functions. Then see the related posts below.
October 20, 2016

Math
ummm, I'd say (3/5)*1200
October 20, 2016

Math
well, 30mi/10mph = 3 hr I assume you can figure what time that makes it...
October 20, 2016

CALC
If you found the mass, you're halfway there. M = ∫ ρ(x,y) dA The x-coordinate of the center of mass is just Mx = ∫xρ(x,y) dA / M and similarly for My.
October 20, 2016

math
If the polynomial has real coefficients, then the complex roots occur in conjugate pairs, so +3i is also a root. So, your description is a bit muddy, but I'd say y = (x-4)(x^2+9)(x-1) That is degree 4. If you want x=1 to be of multiplicity 2, then that would be y = (x-4)(x...
October 19, 2016

Maths
all those words and improper operators. You apparently want (x-3) to be a factor of x^4-3x^3+2x^2-2x+5 recall that the Remainder Theorem says that this will be the case if f(3) = 0. So, evaluate that.
October 19, 2016

math
1 by 81
October 19, 2016

Algebra
It lost 1/2 its value in 5 years. Using a linear model, that is 1/10 each year. So, in 7 years, it will have lost 7/10 of its initial value.
October 19, 2016

math
(a) first step: use scientific notation. (b) Assuming no typo, it is the same (1 times as great)
October 19, 2016

math
I'd double the 1st line and get -4x-2y = 2 -4x-2y = -1 Now what do you think?
October 19, 2016

Maths
fact #1: the two numbers are x and x+24 fact #2: ... then solve for x.
October 19, 2016

Calculus
profit = revenue - cost = demand * price - cost = x*p(x)-c(x) = x(.78+.003x) - (480-.32x+.0005x^2) = 0.0025x^2 + 1.1x - 480 marginal profit = dp/dx = 0.005x^2 + 1.1 p'(700) = 0.005*700^2 + 1.1 = 2451.1
October 19, 2016

Gph
If you know you are wrong, would it not behoove you to study a bit more? How about starting here: http://www.atmo.arizona.edu/students/courselinks/fall12/atmo336/lectures/sec1/humidity.html
October 19, 2016

math
(3x)(4x)(5x) = 20580 60x^3 = 20580 ...
October 19, 2016

Algebra 2
what? Can't plug in a value for x and evaluate? For example, f(23) = 4*23-2 = 90 direct variation means that y = kx So, plug in the numbers and find k.
October 19, 2016

math
well, what is 19+28 ? add that to 21
October 19, 2016

Calculus
1/9, since it's 3x^2 don't you read your own equations?
October 19, 2016

Calculus
This is just the Mean Value Theorem. Find c such that f'(c) = (f(4)-f(0)/(4-0) = 16/4 = 4 Since f'(x) = 2x, where does 2x=4? y-4 = 4(x-2) http://www.wolframalpha.com/input/?i=plot+y%3Dx%5E2,+y%3D4(x-2)%2B4,+y%3D4x
October 19, 2016

Calculus
f' = -1/x^2 + 1 = (x^2-1)/x^2 f'(1) = 0 so, using the point-slope form, y-2 = 0(x-1) or, y=2 http://www.wolframalpha.com/input/?i=plot+y%3D1%2Fx+%2B+x,+y%3D2,+0+%3C%3D+x+%3C%3D+2
October 19, 2016

math
in a town of 9000 people, 7000 died. What portion lived?
October 19, 2016

geometry
15 cos19° and 15 sin19° Looks like it's time to review the basic trig functions.
October 19, 2016

math
tanθ = 191/(4*5280) note that for small angles (in radians) tanθ ≈ θ
October 19, 2016

MATH
What are you measuring? assign variables for the quantities of interest. What are the constraints?
October 19, 2016

calculus
sure looks like -4 to me. You had to ask?
October 19, 2016

Trig
Apparently this is a bizarre attempt to write a fraction. Try using parentheses and virgules, as in (cscθ+1)/(cscθ-1) or something
October 19, 2016

geometry
draw two adjacent angles. I think the answer will be clear. If not, which statements do you know are true?
October 19, 2016

physics
The three blocks are accelerated in the amount of a = F/m = 14.3/(1.1+2.72+4.05) = 1.817 m/s^2 They all have that same acceleration. So, since the 1.1kg block is only pushing 2.72+4.05 kg, its force is F=ma Similarly, the last block is pushed with a force of 4.05a N
October 19, 2016

Calc
looks like ∫[-3,3] ∫[2,19-y] ∫[-√(9-x^2),√(9-x^2)] dy dz dx
October 19, 2016

calculus
you do need the () around 1/x, since powers are done first, and you don't want (e^1)/x 3+e^(1/x) is never zero, so there are no discontinuities because of a zero denominator. However, since 1/x is undefined at x=0, there is a jump there. lim as x->0- = 5/3 lim as x->...
October 19, 2016

G.p.
see the related questions below
October 19, 2016

Geometric progression
Well, you just didn't catch my typo. c*e = (1/3)r^3 * (1/3)r^5 = (1/3)* (1/3)r^8 = (1/3)(432) = 144 So, my correction was wrong. Clearly you did not examine my work to see where the mistake was made. You just threw up your hands and complained I was wrong. Bad form, I must...
October 19, 2016

Geometric progression
oops. (1/9)(432)
October 19, 2016

Geometric progression
(a)(ar^8) = a^2 r^8 = 432 c*e = ar^3 * ar^5 = ...
October 19, 2016

A.p.
If there are n means, then [x,3x] is divided into n+1 intervals. Thus, you have an arithmetic sequence where a = x d = (3x-x)/(n+1) = 2x/(n+1) x, x + 2x/(n+1), x + 4x/(n+1), ... x + 2nx/(n+1), x + 2(n+1)x/(n+1) = x, (n+3)/(n+1) x, (n+5)/(n+1) x, ... 3(n+1)/(n+1) x
October 19, 2016

A.p.
n/2 (2a + (n-1)d) = 3n^2+2n 2an + dn^2 - dn = 6n^2+4n dn^2 + (2a-d)n = 6n^2+4n d = 6 2a-d = 4, so a = 5 Tp = 5+(p-1)(6) = 6p-1 check: the AP is 5,11,17,23,29,... S1 = 5 = 3*1^2+2*1 S2 = 16 = 3*2^2+2*2 S3 = 33 = 3*3^2+2*3 S4 = 56 = 3*4^2+2*4 ...
October 19, 2016

Algebra
Just do a long division. Add what you need to make the remainder zero.
October 19, 2016

Math
3/15 are blue (in math)
October 19, 2016

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