Wednesday
January 18, 2017

Posts by Steve

Total # Posts: 47,946

precalculus
come on. just substitute it into the other equation. t = 2y+2 x = t^2-6 = (2y+2)^2-6 = ... It is clearly a horizontal parabola
December 13, 2016

precalculus
well, t = 2y+2, so use that
December 13, 2016

precalculus
well, |cos3?| <= 1 cos3?=0 when 3? is an odd multiple of ?/2
December 13, 2016

precalculus
the ellipse looks good, but y=-t^2 x=-t^2+4 becomes x-y=4 not x-y^2 = 4 same for t^3
December 13, 2016

Pre-algebra PLease help
I get: 1C 2B 3C (2/3 is just 2 * 1/3) 4A 5A 12 is 50% of 24 That is a good first estimate. However, you are correct that 11 is closer (.48*23.95 = 11.49). I would have guessed 12, but 48% is a bit less than 50%, and 23.95 is a bit less than 24, so my estimate was a bit high. ...
December 13, 2016

chemistry
how many moles of SiO2? Each mole needs 3 moles of C. similarly for the other parts. work with moles, then back to grams.
December 13, 2016

ALGEBRA 2
g(x) = f(x-8)-7
December 13, 2016

algebra
ummm ... h?
December 13, 2016

math
cosx/(secx-tanx) = cosx / (1/cosx - sinx/cosx) = cosx / (1-sinx)/cosx = cos^2x / (1-sinx) = (1-sin^2x)/(1-sinx) = (1+sinx)(1-sinx)/(1-sinx) = 1+sinx why the word "plus"? You have a missing + key?
December 13, 2016

precalculus
Hmmm. The standard form for the polar conics is r = ep/(1 + e sin?) While your equation looks correct, I'd have written it as r = (5/2) / (1 + (5/4) sin?) to make it clear what the parameters are. Or, if you dislike fractions, r = 10/(4+5sin?)
December 13, 2016

Alegrebra 2
horizontal axis or vertical? Where is the vertex or directrix? You need to give more information. Depending on the vertex, many parabolas have that focus.
December 13, 2016

Math
construct AB with length 4.8 find the midpoint M of AB with M as center, draw a circle P with radius 3.6 with B as center, draw a circle Q with radius 5.2 Where P intersects Q is C.
December 13, 2016

precalculus
the rotation angle ? is such that tan2? = B/(A-C)
December 13, 2016

Math grade 6, two-part problem
If the four had amounts w,x,y,z then we know that w+x+y+z = 60 w = (x+y+z)/2 x = 2/3 (y+z) y = 3z w,x,y,z = 20,16,18,6 Amy = w = 20 Nick-Cal = x-z = 16-6 = 10
December 13, 2016

precalculus
after all the similar exercises we have done, you still have no work of your own to show?
December 13, 2016

Math
no, the empty box is there so you can subtract it and see how much was crackers, not "tare weight" as it is called.
December 13, 2016

Math
the mass of crackers in one box is p-0.2 kg so, multiply that by 5 and you get 5p-1 kg So if you got several results, why did you not bother to show how you arrived at each? Maybe one of them was right!
December 13, 2016

mathes for management
enter your data at this site for all the details: http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
December 13, 2016

Calculus AB
what you want is the moment when the particle changes direction. That is, when v(t) = 0. t=2 is the first such time, so you just want s(2) = 55 a(2) = -18 Makes sense, since the velocity is changing from + to -, that the acceleration would be negative. If you want the values ...
December 13, 2016

Algebra
the slope of AC is -1/3 Thus the line AC is y-2 = -1/3 (x+3) The diagonals are perpendicular bisectors. The midpoint of AC is (3,0). The slope of BD is 3, so the line BD is y-0 = 3(x-3) Note that you don't need the other vertices B and D.
December 13, 2016

physics
<0,4> + <3.46,-2> = <3.46,2> = 4N 30 degrees above the x-axis. Makes sense. Since the two vectors are the same magnitude, and 120 degrees apart, their resultant will be 60 degrees from each.
December 13, 2016

Math
the outside diameter d = 2.5/3.14 = 0.796 So, the inside diameter is 0.796-0.0625 = 0.734
December 13, 2016

math
100gal * 8.34lb/gal = 834 lb 100gal * 0.71kg/L * 2.2lb/kg * 3.78L/gal = 590 lb or, note that 1kg/L = 8.34lb/gal
December 13, 2016

Math
-3(x-5y)+1÷2 (4x-10y) assuming you mean -3(x-5y)+1 --------------- 2(4x-10y) that is (-3x+15y+1)/(8x-20y) Your syntax is a bit ambiguous. And where do you get off using the multiply operator (×) for a variable (x)? Seems a lot of trouble.
December 12, 2016

h.p.
your sum is n ? (3k-2)^2 = ?9k^2 - 12?k + ?4 k=1 ?k^2 = n(n+1)(2n+1)/6 ?k = n(n+1)/2 ?4 = 4n Add them up and you have 9n(n+1)(2n+1)/6 - 12n(n+1)/2 + 4n = n(6n^2-3n-1)/2
December 12, 2016

math
if we let t = ?x, we have t^2-6 = t t^2-t-6 = 0 (t-3)(t+2) = 0 t = 3 or -2 so, x = 81 or 16 But, since ?x is positive, only x=81 satisfies the original equation. So, the extraneous solution can arise even when the original equation is not squared. Trying to use x=16 gives us ?...
December 12, 2016

Math
3/10 * 5/10
December 12, 2016

reading and preschoolers
I don't know what the prevailing educational theory is, but the best thing you can do to help your kids enjoy reading is to read to them. That way they learn to associate reading with enjoyable experiences, and they will want to keep on reading even when story time is over...
December 12, 2016

Math
{-4,-3,-2}
December 12, 2016

math
10 - 6 = 4 4 + 10 = 14
December 12, 2016

math
land distance: x water distance: ?(1^2+(2-x)^2) Now determine the cost c(x) and find its minimum.
December 12, 2016

math
what platform? volume = area * height = 40h the well's volume is pi r^2 h = 56pi so, 40h = 56pi
December 12, 2016

precalculus
x = 4cos(t) y = 2sin(t) x^2+4y^2 = 16cos^2(t)+16sin^2(t) = 16
December 12, 2016

Math
again? What do you know about converses? p?q but what does that say about q?p ?
December 12, 2016

math
If you want to solve it, then let u=2/(x-2). Then you have u^2-3u+2=0 (u-2)(u-1) = 0 so, u=1 or u=2 Substitute that back for x and then you can find the solutions.
December 12, 2016

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

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