Wednesday
February 22, 2017

Posts by Steve

Total # Posts: 48,712

Pre-Calculus
think about it. (x+y)^n has + signs for all the terms. (x-y)^n has minus signs for all the odd powers of n, since that is the same as (x + (-y))^n I'm sure you can provide your own examples. You might also try this web site: http://www.wolframalpha.com/input/?i=(x-y)%5E5 ...
December 12, 2016

h.p.
time to do some thinking, using what you already know. Your sum is ?k(k+1)(2k+1) = 2k^3 + 3k^2 + k = 2?k^3 + 3?k^2 + ?k These are just special sums whose formulas you already know.
December 12, 2016

math
what do you mean by "completes"? The sequence goes on forever, as indicated by the ellipsis. And, you don't provide any choices anyway...
December 12, 2016

math
y:g = 15:3 = 5:1 = 35:7
December 12, 2016

h.p.
Your sum is 1/2^2 (1/1.2 + 1/2.3 + 1/3.4 + ...) = 1/4 ? 1/(k(k+1)) Didn't we just do this?
December 12, 2016

differentiation
http://www.wolframalpha.com/input/?i=derivative+(x%5E3%2Byx%5E3)xy%3Dx%5E5-y%5E5
December 12, 2016

differentiation
(x^3+yx^3)xy=x^5-y^5 Hmmm. I'd pull out that x^3 first, giving (1+y)x^4y=x^5-y^5 (y')(x^4y)+(1+y)(4x^3y+x^4y') = 5x^4-5y^4y' Now expand some to get the y' terms: x^4yy' + (1+y)(4x^3y) + (1+y)(x^4y') = 5x^4-5y^4y' y'(x^4y + (1+y)x^4 + 5y^4...
December 12, 2016

Geometry
think of your standard 30-60-90 right triangle, and the ratios of its sides.
December 12, 2016

h.p.
what question? You have the sum correct.
December 12, 2016

h.p.
since 1+2+...+k = k(k+1)/2 Your sum is n ? 2/(k(k+1)) k=1 see what you can do with that. Note that 1/(k(k+1)) = 1/k - 1/k+1
December 12, 2016

Pre-Calculus
well, just look at the differences: 1st differences: -2 2 6 10 2nd differences: 4 4 4 Looks quadratic to me.
December 12, 2016

precalculus
well, you know that the parabola y^2 = 4px has vertex at (0,0) focus at x=p directrix at x = -p The vertex is halfway between the focus and the directrix, at (6,-2) So, shift it right 6, down 2. Then note that the distance from the focus to the directrix is 8-4=4=2p, and you ...
December 12, 2016

precalculus
nope. See your next post. Your parabola has focus (-5/2, -2) directrix x = 11/2
December 12, 2016

math
1 2/3 (4 5/6 + 7 8/9) = 21 11/54
December 12, 2016

Calculus
the radius r is given by r^2+h^2 = s^2 r^2+h^2 = 25 h = ?(25-r^2) v = ?/3 r^2 h = ?/3 r^2 ?(25-r^2) So, for maximum v, find r when dv/dr = 0
December 12, 2016

Math
no. The converse is unknown.
December 12, 2016

Algebra
rearrange the equations. You have x+7y=34 x+7y=32 Surely it is clear that there is no common solution.
December 12, 2016

Pre-Calculus
Just replace every k with k+1. No math involved.
December 12, 2016

Calculus
just because the graph is a horizontal line, it is not necessarily the line y = 0
December 12, 2016

Math (please check my answer)
wow. Your two answers are the givens. Way to go. vertical angles SAS
December 12, 2016

precalculus
actually, you are correct, since 5pi/3 is in QIV, so with r = -14, the point is in QII, with y positive.
December 12, 2016

algebra
diam=8, so r=4 area = 2?rh = 52 h = 52/(2?r) = 13/(2?) v = ?r^2 h = 16? * 13/(2?) = 104
December 12, 2016

Physics
This article should get you off the ground, as it were ... https://en.wikipedia.org/wiki/Trajectory
December 12, 2016

math
3+4+5 = 12 You want their sum to be 24, so double each value.
December 12, 2016

HELP MATH
14 4/10 - 10 5/10 = ?
December 12, 2016

Pre-Calculus
well, just add on a k+1 term. Looks like (A) to me
December 11, 2016

math
p = 3 s = 3(2 1/2) = 7 1/2 r = 3 - 3/4 = 2 1/4 t = (2 1/4)(1 1/3) = 3 now just add 'em up
December 11, 2016

Algebra
the new dimensions are 6w and 6h, so the area is 24 * 6^2
December 11, 2016

calc
lim (1 + 1/x)^x log lim = lim x log(1 + 1/x) = lim log(1 + 1/x) / (1/x) = lim (-1/(x^2+x)) / (-1/x^2) = lim x^2/(x^2+x) = 1 so, log lim = 1 lim = e^1 = e
December 11, 2016

Algebra
you are correct: 2(x+4)(x+3)= 3(x+2)(x-1) 2(x^2+7x+12) = 3(x^2+x-2) 2x^2+14x+24 = 3x^2+3x-6 x^2-11x-30 = 0 Now use the quadratic formula.
December 11, 2016

Math! Help!
the domain of all polynomials is (-?,?). Remember that.
December 11, 2016

Math! Help!
type in your polynomials here, and see the details. http://calc101.com/webMathematica/long-divide.jsp
December 11, 2016

Algebra
h(2h-3)/2 = 126 2h^2 - 3h - 252 = 0 you are correct
December 11, 2016

precalculus
nope. The standard form for a conic is r = ep/(1 ± e sin?) try again
December 11, 2016

Algebra
there is always a b. In this case, it is zero! 2x^2+16 = 0 2(x^2+8) = 0 2(x+?8 i)(x-?8 i) = 0 ...
December 11, 2016

Algebra
so, did you apply one of the methods? recall that (a+bi)(a-bi) = a^2+b^2
December 11, 2016

Algebra
complete the square quadratic formula
December 11, 2016

English
yes. watch the capitalization, though: I said, "Where do you live?"
December 11, 2016

English
1 and 2 are common, and equivalent. #3 means that it was necessary to stay -- not leave. #4 would get raised eyebrows and a "huh?"
December 11, 2016

Geoemtry
just subtract the picture area from the total, and that is the area of the frame: (x+2*2)(x+2*4)-x^2 = 65.25
December 11, 2016

Geoemtry
No idea. What is x supposed to represent?
December 11, 2016

Algebra
-12 >= x^2+8x x^2+8x+12 <= 0 (x+2)(x+6) <= 0 You know the roots are -2 and -6, and the parabola opens upward. So, y is negative between the roots: -6 <= x <= -2 Clearly Philip did not check his answer.
December 11, 2016

Algebra 2
m = ks^6 m/s^6 = k a constant If m is replaced with 15m, then you want a new s such that 15m/s^6 = m/2^6 s^6 = 15*2^6 s = 2*15^(1/6) = 3.14 mi/hr
December 11, 2016

AP Calculus AB
If x = side parallel to river y = other sides So, you want to maximize a = xy subject to 12x + 4*2y <= 3600 See what you can do with that.
December 11, 2016

algebra 1
Or, just note that a horizontal line is expressed by the equation y = k for some k. Since we have the point (-3,-7), the line is just y = -7
December 11, 2016

algebra 1
x = -5 is a vertical line. So, you want a horizontal line through (-3,-7) Now, what might that be?
December 11, 2016

algebra
you want 55x to be a perfect square 55 = 5*11 So, if x=55, 55x=55^2 = 3025 and the square root is 55 Any value of x that is 55 times a perfect square will also work.
December 11, 2016

math check my answer please
looks good to me.
December 11, 2016

Algebra
Nope. eq #2 is better to use to substitute. It says x = 6y+49 So, use that in eq #1, and you have 8(6y+49)-11y = 170 48y+392-11y = 170 37y = -222 y = -6 x = 6y+49 = -36+49 = 13 So, where did you go wrong? How did you make this step? -11y = 170-8x y = -15.45 + 72 what did you ...
December 11, 2016

Math
(a) No If it rains, I'll eat chicken. If it rains, I'll go outside. No way to conclude that eating chicken means going outside. (b) Come on. You know that the converse of p?q id q?p. So, ... (c) ~q ? ~r (d) Nope. I'm sure you can come up with an example. (Use what ...
December 11, 2016

math
the volume will be reduced by a factor of (1/3)(1/3)(1/3) = 1/27
December 11, 2016

math
LCM(12,18) = 36
December 11, 2016

Math
google can provide many discussions, all of which will be more complete than what we can provide here.
December 11, 2016

Math
(9/4)^2 * 48
December 11, 2016

Calculus
p = 2x+y a = 1/2 y ?(x^2 - (y/2)^2) = 1/2 (p-2x) ?(x^2 - ((p-2x)/2)^2) = 1/4 (p-2x)?(4px-p^2) da/dx = p(p-3x)/?(4px-p^2) da/dx=0 when p = 3x That is, when the triangle is equilateral. I expect you saw that coming, eh?
December 11, 2016

Geoemtry
if the two sides given are corresponding sides, then they have a common ratio: x/4 = 1/(2x+7) x(2x+7) = 4 2x^2+7x-4=0 (2x-1)(x+4) = 0 x = 1/2 so the triangles have sides of 4,8 and 1/2,1
December 10, 2016

Algebra2
right you are
December 10, 2016

Algebra2
Name the property of real numbers for -2(x+4)=-2x-8 associative property of multiplication communitive property of addition distributive property associate property of addition my answer is distributive property
December 10, 2016

algebra word problem
1100x + 1800y = 288 There is no unique solution. The rates can be anywhere from x=0 and y=16% to x=y=9.93%
December 10, 2016

Algebra
solve for t when h=0.
December 10, 2016

Math (calculus) (mean values)
I agree with the average rate of change. So, you want s'(c) = 1395/28 s'(t) = 1395/(t+2)^2 so, 1395/(c+2)^2 = 1395/28 (c+2)^2 = 28 c = ?28 - 2 ? 3.29 So, the desired month is later than 3, namely 4.
December 10, 2016

Functions - math
fg = (2x+3)(ax^2+b) = 6x^2-21 2ax^3+3ax^2+bx+3b = 6x^2-21 when x=q, we have 2aq^3+3aq^2+bq+3b=6q^2-21 2aq^3+(3a-6)q^2+bq+(3b-21) = 0 check out the solutions to that at this url. The only easy one is in fact when q = -3. http://www.wolframalpha.com/input/?i=2aq%5E3%2B(3a-6)q%...
December 10, 2016

Science
The axial tilt is what causes the seasons, but it does not change. The language of the question and the choices is poorly constructed.
December 10, 2016

h.p.
google is your friend. This should help. http://www.askiitians.com/forums/Algebra/22/42109/progressions.htm
December 10, 2016

Algebra
well, what is h when it hits the ground? ...
December 10, 2016

Calculus
when the water has depth y, the surface has with 4/3 y. That means the volume is v = y(4/3 y)/2 * 15 = 10y^2 dv/dt = 20y dy/dt Now just plug in your numbers to find dy/dt
December 10, 2016

Algebra
This is a trick question. |u| is always positive, so |1-4k| ? -11 for any value of k. Damon's solution is correct, but it should read k >= -2.5 OR k <= 3 So, any value of k will work.
December 10, 2016

Math
profit = revenue - cost revenue = price * demand P(x) = x(200-0.5x) - (100+5x+7x^2) = -7.5x^2 + 195x - 100 Now just find the vertex of that parabola.
December 10, 2016

maths probability
I hope he had fun.
December 10, 2016

Math
well, why do you not simply use the formula? i = P((1+r/n)^(nt)-1) and plug in your values?
December 10, 2016

Math
m/n= (m+b)/(n+b) m(n+b) = n(m+b) mn+mb = mn+nb b(m-n)=0 b=0 or m=n The question is poorly explained. It clearly said Does there exist a fraction(s) m/n... so offering a single example would indeed answer the question!
December 10, 2016

Geometry
15-9 < x < 15+9 so (C) is correct. If it were 24, then the triangle would collapse to just a line.
December 10, 2016

Math
4?/3 r^3 = 15000 r^3 = 45000/(4?) r = 10?(45/4?) or 5?(90/?)
December 10, 2016

math
area has the ratios squared, so 2^2:3^2 = 4:9
December 10, 2016

Math.
also 2:3
December 10, 2016

math check my answer please
Just as ?125 = 5?5, ?b^3 = b?b You went a bit astray, so we should have 3?(125a^1b^3) = 3*5b?(5ab) = 15b?(5ab) The 3 does not distribute across products. The distributive property only applies to addition, as in 3(?a + ?b) = 3?a + 3?b
December 9, 2016

soil mechanic
um ?
December 9, 2016

math help
?(48ab^2) = ?48 * ?a * ?b^2 = ?16 * ?3 * ?a * b = 4b?(3a)
December 9, 2016

Math
sorry. You have the equation. Plug in the given x or y value and solve for e or f. You gotta do something here, dontcha? Stop looking for freebies...
December 9, 2016

Math
Assume a straight line. As x increases by 2 (5-7) y increases by 6 (13-19). So try y = 3x But, 13 - 3*5-2. So, try y = 3x-2 it works for all the known pairs. So, fill in e and f.
December 9, 2016

Math
correct.
December 9, 2016

Math
Nope. The slopes are 1 and -1, so their product is -1. That means they are perpendicular.
December 9, 2016

geometry
google is your friend. Try this: https://www.algebra.com/algebra/homework/word/geometry/Angle-bisectors-in-an-isosceles-triangle.lesson
December 9, 2016

Geometry
ABE+ABC = 180, so ABC = 180-ABE ABC = (180-y)/2 so, 180-(3x+20) = (180-y)/2 160-3x = 90 - y/2 70-3x = -y/2 y = 6x-140
December 9, 2016

math
no, m+5m = 6m cm area is m*5m = 5m^2 cm^2
December 9, 2016

math
I don't know what you mean by "solve" it. It's just an expression. No equation. (0.08b^{4m+8})/(18b^{m?2}) = .08/18 b^(4m+8-(m-2)) = 1/225 b^(3m+10) 1/(1/5) m^(4-n) * 1/2 m^(n-6) = 5/(2m^2)
December 9, 2016

Calculus
and ... ?
December 9, 2016

Algebra
Draw the line. It lies in QII, QI, QIV
December 9, 2016

precalculus
divide by -2 ant it changes to r = -2/(1+3sin?) now what do you think?
December 9, 2016

precalculus
since tan?/sec? = sin?, can you handle r sin? = 2 ??
December 9, 2016

Algebra 1
yep.
December 9, 2016

precalculus
the standard equation is r = ep/(1 - e sin?) so, if you divide top and bottom by -2 you get r = -2/(1+3sin?)
December 9, 2016

precalculus
tan?/sec? = sin? so, can you convert r sin? = 2 ??
December 9, 2016

math
if the cuboid has sides x,y,z, then the main diagonal d has length d^2 = x^2+y^2+z^2
December 9, 2016

math
That is really a=p(1+r/n)^(nt) Assuming you mean compounded quarterly, just plug in your numbers, with r=0.043 n=4 t=6
December 9, 2016

Math
f+t = 26 5f+10t = 210
December 9, 2016

Algebra
well, that would be 2/9 * 2493, right?
December 9, 2016

Quadratic Relations, Algebra, Math
solve for h = 0.5 -4.9t^2+14t+2.5 = 0.5 now just use the quadratic formula.
December 8, 2016

math
Cause the exponent is positive you move the decimal point 3 places to the right so that would = 1900
December 8, 2016

Algebra
12.50-8.75=3.75 You have $3.75 left for toppings $1.25*3=3.75 You can have 3 toppings
December 8, 2016

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