Friday
July 31, 2015

Posts by Steve


Total # Posts: 32,558

algebra please help
I only see one polynomial.
April 30, 2015

Trigonometry
hey, come on. The y-intercept is where x=0! So, just plug it in y(0) = -2 sin(0-pi/2) = -2(-1) = 2 getting x-intercepts can be hard. Getting the y-intercept is trivial! Don't forget your Algebra I now that you're in trig.
April 30, 2015

Trigonometry
the origin is an x-intercept if f(0) = 0. Is that true here?
April 30, 2015

Advanced Functions
sin4x/(1-cos4x) (2 sin2x cos2x)/(2sin^2 2x) cos2x/sin2x (2cos^2 x - 1)/(2sinx cosx) cosx/sinx - 1/(2sinx cosx) cotx - 1/2 cscx secx
April 30, 2015

Math
the diameter is 14, so the radius is 7 the area is π*7^2 = 49π
April 30, 2015

Math
One way: divide the big volume by the small volume: (3 3/4)(5)(4 1/2) / (1/4)^3 = (675/8) / (1/64) = 5400 Another way: decide how many cubes it takes to fit each of the larger dimensions (3 3/4) / (1/4) = 15 5 / (1/4) = 20 (4 1/2) / (1/4) = 18 So, the prism is 15x20x18 cubes...
April 30, 2015

Math
y=x+(x/4) ? Why not just 5/4 x? Once you get your curves figured out, r = the distance to the inside curve R = the distance to the outside curve You need to solve for x, so you know r. Clearly, R=3, since that's the far boundary. The limits of integration (along dy) are ...
April 30, 2015

Math
assuming the cylinder also has diameter 7, then if the cone has height h and the cylinder has height k, you need π/3 * r^2 h = π * r^2 k h/3 = k The cone needs to be 3 times as tall as the cylinder
April 30, 2015

math
Draw a diagram. You have a 30-60-90 triangle, with the tree at the right angle. You want the altitude from the tree to the road. The distance of the tree from B is 200 The distance of the tree from A is 200√3 So, h = 100√3
April 30, 2015

Calculus
with 3 unknowns and only two equations, there will be no unique solution. It should be 13y+5z = 39 so, pick any y and z that fit, and then figure x. Or, you can evaluate y and z in terms of x: y = 5x-7 z = 13(2-x) Now you can pick any value for x, and then figure y and z. In ...
April 30, 2015

Math
1982: (3.35*40+80)(50) = 10700 2015: 10700*1.045^(2015-1982) = 45732.12
April 30, 2015

Math
317.24(1.085)(1.15)+25.00
April 30, 2015

Calculus
just add the vectors. That is the resultant, call it r. The equilibrant is -r: that vector which cancels the resultant, keeping things in equilibrium.
April 30, 2015

Calculus
vectors are just a compact way of describing three independent sets of numbers. You just have 3a-6 = -3 9-2b = 1 6-2b = -2 clearly, a=1, and any value of b will work. since (1,3,2) and (3,b,b) are not collinear, they span R2.
April 30, 2015

Math
pq-pr-qp+qr-rp+rq or, arranging factors alphabetically, pq-pr-pq+qr-pr+qr -2pr+2qr 23ab-12ab - 12bc^2-13bc^2 11ab - 25bc^2
April 30, 2015

Math
just plug and chug: 2(-7/2)^2 - 9(-7/2) + 7 ...
April 30, 2015

Math
nothing to solve. just evaluate the expression 3(-1.3)(2/5) - |-1.3-2| -1.56 - |-3.3| -1.56 - 3.3 -4.86
April 30, 2015

Math
(3245.50-143.15)(1-0.10) = 2972.115
April 30, 2015

Calculus
dy/dx = (1+x)/xy y dy = (1+x)/x dx 1/2 y^2 = lnx + x + c since y(1) = -4, ln 1 + 1 + c = 8 c = 7 1/2 y^2 = lnx + x + 7 . . .
April 30, 2015

math
pi * 9^2 * 4
April 30, 2015

math
if the digits are a,b,c we see that a=4 Then we are doomed. If b and c are both odd, they cannot sum to 5, which is also odd. And how about a little punctuation? That run-on sentence is very annoying.
April 30, 2015

Algebra 2
Is there a question in there somewhere?
April 30, 2015

math
just subtract what was used from the original amount: 9100 - 321*28.286 However, that assumes that all the leftover parts could be combined to form new circles; not very likely. A better way to look at it is to decide how many rows and columns of discs could be cut. 130/6 = 21...
April 30, 2015

SOLVE -MATH
9C6 * 6C3
April 30, 2015

physics
we have, since the focal length is constant, 1/f = 1/20 + 1/x = 1/16 + 1/(x+2.7) Just solve for x, and then find f.
April 30, 2015

Calculus
good work. Confirm with the graphs at http://www.wolframalpha.com/input/?i=plot+x%5E2%2B3x%2B2%2C+y%3D3x%2B2+for+-1+%3C%3D+x+%3C%3D+1
April 30, 2015

maths
you have a common ratio, so p/-6 = -32/p p^2 = 192 ...
April 30, 2015

math
No, P(black) = 9/10 1 - 9/10 = 1/10 B is the odds of drawing a white, not the probability.
April 30, 2015

Physics
1A is 1C/s You have 73mC/9s = 8.11mA the net charge is not relevant here, since all we need is the number of Coulombs.
April 30, 2015

MAT 142
keeping all the measurements in yards, (15/3)(8/3)(8/36)($30)
April 30, 2015

Math
clearly you can drop the trailing zeros, getting 504/5940 both are even, so you can factor out 2 top and bottom: 252/2970 and again: 126/1485 now 3's: 42/495 and again: 14/165 That's as far as you can go. Or, you can factor both numbers. 5040 = 2^4 3^2 5 7 59400 = 2^3 ...
April 30, 2015

Math
(8*7)/2 - π/4*3^2
April 30, 2015

math
hmmm. None of the polynomials factors over the reals, so I don't see any help there. Looks like GCF=1 and LCM = (1+4x+4x^2-16x^4)(1+2x-8x^3-16x^4)(16x^4+4x^2+1) if x=-1 we have -17,-7,21 x=0 we have 1,1,1 x=1 we have -7,-21,21 x=2 we have -231,-315,273
April 30, 2015

math - eh?
what's with the .. ?
April 30, 2015

Math
first expand: 4x^3y+30x^2y-35xy^2-72x^2y+80xy^2-11xy^2 then combine: 4x^3y-42x^2y-34xy^2
April 30, 2015

Math
(4)(14)+(-1)(3)+(-6)(8) = 56-3-48 = 5 Pretty grim score, eh?
April 29, 2015

English
What do you do when the author can't be found? How do you cite the book? Would use just the title of the book or explain that the info is missing?
April 29, 2015

English
what should you do if you need to cite a book for which you don't know the author?
April 29, 2015

Algebra 2
multiply through by 8x and you have 2(x+2)-3(4) = x 2x+4-12 = x x = 8 check: 10/32 - 3/16 = (10-6)/32 = 4/32 = 1/8
April 29, 2015

Math
to be a perfect square, all its prime factors must be squared. Since 7 occurs an odd number of times, 7^2 cannot divide the number. So, no, it is not a perfect square. It is almost a perfect square, though, since 2^6 * 3^10 * 5^12 * 1^18 = (2^3 * 3^5 * 5^6)^2
April 29, 2015

Math
6789 = 3*31*73 since 3,31,73 all divide the first term, and 6,62,146 all divide the second term, 6789 divides both terms, and thus the sum as well.
April 29, 2015

Math
all the powers must be a multiple of 3. So, it is a perfect cube. It is (2^3 * 3^4 * 5^2 * 7)^3
April 29, 2015

MATH
d = 7n 10d = 650+5n 10(7n) = 650+5n 65n = 650 n=10 so, d=70
April 29, 2015

Molar mass
so, what steps did you follow? If you want help with your error, show your work...
April 29, 2015

Mathematics
just plug and chug: 148225 - x^2 = 578132.1225 - 406278.76 + 1274.8x - x^2 x = -18.535
April 29, 2015

pressure
PV=nRT Just plug in your numbers and solve for P.
April 29, 2015

math
440x220 with the 440' side parallel to the river. the related questions below provide steps for the solution.
April 29, 2015

Math
if it is a perfect square, all of its prime powers will be even. Since if you have (2^a 3^b 5^c ...)^2 all the exponents are doubled.
April 29, 2015

math: fundamental counting principal
12*10*7*5
April 29, 2015

math; solve problem
the simplest solution is 32.2*21/13.65
April 29, 2015

Math
The problem is poorly worded. Why don't you draw a diagram, and tell us what the relevant points of reference are?
April 29, 2015

MATH; STANDARD DEVIATION
you can plug in your numbers and play around with Z table stuff at http://davidmlane.com/hyperstat/z_table.html
April 29, 2015

Algebra
y=0 at x = -1 for x > -1, y is increasing
April 29, 2015

Pressure
PV=kT, so P/T is constant Figure the increase in T (as a factor), and apply that same factor to P to keep the ratio constant.
April 29, 2015

Math Help
what, you can't plug in values for n? a1 = 1(1^2-6) = 1(-5) = -5 a2 = 2(2^2-6) ... a1=14 a2 = (-2)(14) = -28 a3 = (-2)(-28) ...
April 29, 2015

Math
GCF=1 LCM=pq
April 29, 2015

math
3x2 + 3x5 = 6+15 = 21 8x3 = 18 So, he needs more canvas than he has. Or, you could line up the two desired pieces, and he needs one large piece 3x(2+5) = 3x7, but his piece is only 3x6.
April 29, 2015

algebra NEED HELP
√(x-5) is always positive. So, there is no solution √(2-7x) = 2x 2-7x = 4x^2 4x^2+7x-2 = 0 (x+2)(4x-1) = 0 so, x = -2 or x = 1/4 But since √(2-7x) is positive, x = -2 is an extraneous solution So, x = 1/4 is the only solution
April 29, 2015

algebra
since y=kx, y/x is constant. Thus, 14/21 = 7/x
April 29, 2015

Calculus and Vectors
the resultant is <900/√2,-900/√2 + 100> Now just find the speed and direction.
April 29, 2015

Calculus
They span R2 if they are independent. That is, the 2nd is not a multiple of the 1st. So, what do you think?
April 29, 2015

Math help Steve?
right on
April 29, 2015

Math
well, you need 3x+4 = 16 or 3x+4 = -16
April 29, 2015

Last week Help Math
now way to tell about the median and mode, but the mean is changed from (10*10000)/10 to (9*10000+20000)/10
April 29, 2015

Calculus
Draw a diagram of the forces. tanθ = 76/220
April 29, 2015

Math (check answers)
#1 Nope (C) is (x+3)(x-1)(x-5) You want (x+3)(x+1)(x-5) #2 Nope There are a total of 11 votes, so for is 7/11 = 64%
April 29, 2015

Math help!
If the vertical lines have length y, and the horizontal sides have length x, then 3y+2x = 270 and the total area is a = xy = x(270-2x)/3 = 90x - 2/3 x^2 This is just a parabola with vertex at (135/2,6075/2), so the total area is 6075/2. Since x=135/2, y=45 Since the inside ...
April 29, 2015

Calculus-limits
take derivatives top and bottom. The desired limit is the same as the limit of (cosx-0)/1 = cosx Now take the limit as x->a so, (b) is the answer.
April 29, 2015

math
is that 13 in high? Presumably the circular top has the same circumference as the cylinder.
April 29, 2015

math
(a+36d)/(a+20d) = 7/4 (a+64d)/(a+36d) = 7/4 3a=4d looks like there are many such sequences: a=12, d=9 T21 = 192 T37 = 336 T65 = 588
April 29, 2015

Algebra
the angle is x, where tan(x) = 2/(30*12)
April 29, 2015

Mathh
note that y grows by 3 when x grows by 1. That means you can start with y = 3x But since y(0)=1 instead of 3*0=0, y = 3x+1
April 29, 2015

Calc 1
If the triangle has side x, then the area a = ((11-3x)/4)^2 + √3/4 x^2 That's just a parabola. Its vertex will be the minimum area. For maximum, check to see which is greater: a(0) or a(11).
April 28, 2015

math
do you know how to calculate the length of a helix? The radius is 2/π, so we have x = 2/π cos θ y = 2/π sin θ z = 15/4π θ 0 <= θ <= 8*2π
April 28, 2015

calculus
dy/dx = y^2/x^3 dy/y^2 = dx/x^3 -1/y = -1/(2x^2)+c y = 2x^2/(1-cx^2) what's with all the verbal noise? You want to discuss y' = 2x√(1-y^2)? Just say so dy/√(1-y^2) = 2x dx arcsin(y) = x^2 + c y = sin(c+x^2)
April 28, 2015

Geometry
the front wheel makes 6/10 of a turn for every turn of the rear wheel. So, the pedals move (6/10)*2pi*7 inches during that time.
April 28, 2015

math
.5L/s * 3.7gal/L * 3600s/hr = ? gal/hr
April 28, 2015

Calculus
f(x) = ax^2 + 1/3 for x >= 1 bx - 10/3 for x < 1 so, we need f(1) to be consistent. That is, a + 1/3 = b - 10/3 we also need f'(1) to be consistent: 2a = b so, a + 1/3 = 2a - 10/3 a = 11/3 b = 22/3 a+b = 11
April 28, 2015

Math help
well, what is (3√2)^3 ?
April 28, 2015

Calculus
actually, I misspoke. You want p when h=8200, so p(8200) = 101.3 e^(-.000151*8200) You should have caught that typo...
April 28, 2015

Calculus
dp/dh = kp dp/p = k dh ln p = kh+c p = c*e^(kh) p(0)=101.3, so c=101.3 p(h) = 101.3 e^(kh) p(1000) = 87.1, so 101.3 e^(1000k) = 87.1 1000k = ln(87.1/101.3) k = -.000151 p(h) = 101.3 e^(-.000151h) so, now solve for h when p = 8200
April 28, 2015

Calculus
120 sin 25° think about it -- a horizontal force (0°) does no lifting, and an upward force (90°) is all lift.
April 28, 2015

Physics - Half Life Question Check!!!
The amount left after t billion years is (1/2)^(t/1.25) So, you want (1/2)^(t/1.25) = 0.77 t/1.25 log 0.5 = log 0.77 t = 1.25 log(0.77)/log(0.5) = 0.471 Looks like (B) to me.
April 28, 2015

Geometry
a = 1/4 √3 (36/3)^2
April 28, 2015

Algebra Word Problem
if there are x price increases, the revenue is (95-x)(100+x) That is just a parabola. Its vertex represents maximum revenue.
April 28, 2015

Calculus
your logic and your answer are correct.
April 28, 2015

Calc
wold that not be just the integral of C' from 3500 to 8500? Just use the power rule for each term.
April 28, 2015

Calculus help??
f(x) = ∫[0,x] 2πu du df/dx = 2πx you are correct. I suspect that those choices belong to a different problem, or that there is a misprint in this one.
April 28, 2015

Calculus I
The question is, how many can you sell at $10? Let's say it's 1000. Then if there are x price reductions, you can sell 1000+500x So, the revenue will be (1000+500x)(10-x) The cost is 3000+2(1000+500x) profit is revenue - cost. Use your real value instead of 1000, and ...
April 28, 2015

Math Check
both right
April 28, 2015

Math Check
Both look good to me.
April 28, 2015

math
the left side is also just a difference of two squares, so ((a-3)+(a-2))((a-3)-(a-2)) = (2a-5)(-1) so, you have 5-2a = 5 a = 0
April 28, 2015

Math
it's a problem in exponential growth similar ones in exponential decay are things like radiocarbon dating, where the amount of carbon-14 diminishes each year by a certain small percentage.
April 28, 2015

Math
after t minutes, there are 2^(t/15) bacteria. So, find t when 2^(t/15) = 10000 t/15 log2 = log10000 t = 15 * (log10000/log2)
April 28, 2015

math
if the side of the base is s, then you know that 10s^2 = 810 The total area is the base (x^2) and 4 sides, each of area 10x.
April 28, 2015

math
the base is 18*18 each side is a triangle of base 18 and height 12, so the faces have area 4*(18*12/2) SO, just do the math.
April 28, 2015

Algebra
3x = 7*8/21 x+2 = 5*20/10 That should get you started
April 28, 2015

math
v = Bh so, 9B = 2025
April 28, 2015

chemistry
You Can Get Your All Chemistry and other subjects questions Solved just Visit: http://www.myassignmenthelp.net/data-structure-assignment-help.php
April 28, 2015

5th grade (math)
the difference between two numbers is found by subtraction: 13 1/10 - 12 1/2 = 12 11/10 - 12 5/10 = 6/10 or 3/5
April 28, 2015

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