Saturday
December 10, 2016

Posts by STEVE

Total # Posts: 47,054

Functions
Oh come on. Just plug in their definitions: g(x) = f2(x)-f3(x) = (1/8(x+16)^2-98)-(2x+24) = 1/8 x^2 + 2x - 90 f1(x)=0 is stupid, as it contributes nothing.
November 18, 2016

Functions - huh?
Determine an equation for this function WHICH function?
November 18, 2016

Calculus
the chain rule says that d/dx(fg) = f'g + fg' not f'*g'
November 18, 2016

Calculus
clearly, y(0) = 4 y'(0) = 0 So, a parabola with vertex there will work: y = 2x^2+4 or how about a cosine function? y = 4cos(x)
November 18, 2016

math
In standard form, x^2/9 + y^2/4 = 1 a = 3 b = 2 c = ?5 You are correct that the foci are at (±?5,0) The directrices are at x = ±a^2/c = ±9/?5
November 18, 2016

math
Clearly the distance z between the ships can be found using z^2 = (Ax-Bx)^2 + (Ay-By)^2 = (-t+20)^2 + (-2t+10)^2 = 5t^2 - 80t + 500 2z dz/dt = 10t-80 dz/dt = 0 when t=8. So, just evaluate z at t=8.
November 18, 2016

Algebra
#1 clearly A grows by 0.6 for each new term. suppose A(n) = 0.6(n-1) But, when n=0, A(0) = 0.3 so just add that at the start. A(n) = 0.6(n-1) + 0.3 #2 A(n) starts at 47 and drops by 15, so start with A(n) = 47-15(n-1) The (n-1) stuff pops up because the first term (n=1) has ...
November 18, 2016

math
oops. That gives the untranslated parameterization. You want to shift things, so x = sec(t)/3 - 2 y = 4tan(t) + 4 so that 9(x+2)^2 - (y-4)^2/16 = 1
November 18, 2016

math
you know that sec^2(t)-tan^2(t) = 1 so, let x = sec(t)/3 y = 4tan(t)
November 18, 2016

Math
just compare cost/volume
November 18, 2016

Math
a = pi r^2 da = 2pi r dr now just plug in your numbers.
November 18, 2016

Calc
Graph the function. The area is just a couple of triangles.
November 18, 2016

Calculus
sin^2(x^2) * 2x
November 18, 2016

Mathematics
"there" not "their" if the road (or walkway) has width w, then the length is 45-2w
November 18, 2016

Calc
f(3) = 27 f(0) = 0 so, the slope of the secant line is 27/3 = 9 So, you need 3c^2 = 9 c = ?3
November 18, 2016

Algebra
four times a number is 4w so, ...
November 18, 2016

math
There are clearly no real solutions, but you can factor it into (x^2-x+1)(x^2+x+1)(x^4-x^2+1) = 0 because x^8+x^4+1 = x^8+2x^4+1 - x^4 = (x^4+1)^2 - (x^2)^2 a difference of two squares Now you can find the roots of those quadratics
November 18, 2016

math
42
November 18, 2016

math
and inept at following instructions, it appears...
November 18, 2016

Order MATH!
2/3 = 0.66 7/10 = 0.70 now things should be clear.
November 18, 2016

maths
the area is just 1/2 ab the area is just 1/2 bc sin?
November 18, 2016

maths
(a) ? is easy, since the angles sum to 180° Then use law of sines to find b,c (b) this is a right triangle. a^2 = b^2+c^2 then just use the trig functions to get the other two angles. (c) use the law of cosines to get any or all of the angles. Or, having one, you can use ...
November 18, 2016

maths
find the reference angle in QI. only sin x is positive in QII. For example, cos x = ?2/2 x = 45° Since cos x < 0 in QII, that is the only solution. Work the others in like wise.
November 18, 2016

Maths
just list the terms. 6 is the last to appear.
November 18, 2016

Maths
Think of a rectangle. The maximal area is achieved when it is a square. Similarly for a rectangular prism, the maximum volume is when it is a cube. so, in this case, the sum is just 3?2001
November 18, 2016

Geometry
#4 Remember the 3-4-5 right triangle. This is just double that. You got #1 right. How could you not be sure on #4?
November 18, 2016

Geometry
#1 ok #2 the sides are 26/?2 = 13?2 If the sides of a square are 1, the diagonal is not 2. #2 In such a triangle, the sides are 1,?3,2 Now multiply everything by 8. (c) is wrong.
November 18, 2016

math
and how did you arrive at that figure? Take a piece of graph paper and draw a 6x8 rectangle on it. You really think the diagonal is 48? Think of the Pythagorean Theorem here.
November 18, 2016

Math
she got 1/6 wrong. so, ...
November 18, 2016

Calc
I assume you mean x^(2/5) since f' = 2/5 x^(-3/5) it is undefined at x=0
November 17, 2016

Calculus
are they the same?
November 17, 2016

Calculus
a = ?(x/2?)^2 + (14-x)/6 * (14-x)/3 P = (12+x)(27-3x) - (4x)
November 17, 2016

calculus
11,33,55,77,99,121,319,517,539,...,979
November 17, 2016

Math
see related questions below
November 17, 2016

mathematics
no idea. Where is D?
November 17, 2016

Math algebra
(20+2w)(30+2w) = 936 w = 3
November 17, 2016

Algebra
you want x^2+y^2+6y+5 = x^2+y^2-2x-8 6y+5 = -2x-8 y = -(2x+13)/6 Now use that to find x: x^2 + (-(2x+13)/6)^2 - 2x - 8 = 0 40x^2 - 20x - 119 = 0 x = [5±9?15]/20 y = -3/20 (15±?15) http://www.wolframalpha.com/input/?i=solve+x%5E2%2By%5E2%2B6y%2B5%3D0,+x%5E2%2By%...
November 17, 2016

math
a = bh/2 so, 5b/2 = 15
November 17, 2016

Linear Programming - The Graphical Method
This web site is very useful: http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html
November 17, 2016

Math (equation of tangent line)
2xy-1=(x+y+1)^2 2y + 2xy' = 2(x+y+1)(1+y') 2y + 2xy' = 2(x+y+1) + 2(x+y+1)y' y' (2x - 2(x+y+1)) = 2x+2 y' = -(x+1)/(y+1) So, your derivative is ok. when y = -1, x = -1, so y' = 0/0 so, what happens near (-1,-1)? If y = -1+h, x = -1+h+?(2h) so, y'...
November 17, 2016

Pre-Calc
sin(kx) has period 2?/k tan(kx) has period ?/k so, crank it out.
November 17, 2016

ELITRICAL MATH! (LAST ONE FOR TODAY, HOPEFULLY!)
divide cost/quantity $1.49/3ft = $0.4967/ft and similarly for the other one. Then compare
November 17, 2016

Math
8^-2 = 1/8^2 = 1/64 4^-2 * 2^0 = 1/16 * 1 = 1/16 5^(2-1+3) = 5^4 Your typos make things hard to read
November 17, 2016

Math
yes.
November 17, 2016

Math
just substitute: y = x-2, so x^2 - x(x-2) + 3(x-2)^2 = 15 3x^2 - 10x - 3 = 0 solve for x, than y=x-2.
November 17, 2016

Math
6 * 1/3 = 2
November 17, 2016

Algebra
You have two circles: x^2 + (y+3)^2 = 6 (x - 9/2)^2 + y^2 = 105/4 Naturally, they intersect where x^2+y^2+6y+3 = x^2+y^2-9x-6 6y = -9x-9 y = -(3x+3)/2 Subbing that into one of the equations, x^2+(3x+3)^2/4-9x-6=0 13x^2 - 18x - 15 = 0 x = 1/13 (9±2?69) y = -3/13 (11&...
November 17, 2016

Math
well, g = f-7 so what do you think?
November 17, 2016

Math
The only reason I can think of is that a measurement is subject to error (and is really only a decimal approximation), whereas the PT results is exact.
November 17, 2016

Differential Calculus
I do not know what cos^y means. I'll just use cosy and you can fix it as needed. x^2 cosy - siny = 0 2x cosy - x^2 siny y' - cosy y' = 0 y' = (2x cosy)/(x^2 siny + cosy) so, at (0,?), y' = 0 Since the tangent is horontal, the normal is vertical, and the ...
November 17, 2016

maths
40 = 360/9 so, 1/9 of the whole area.
November 17, 2016

maths
35 min = 7/12 of an hour. That is, 7/12 of the circumference of a circle with radius 6 cm. so, ...
November 17, 2016

Algebra
correct
November 17, 2016

Math
add up the total points so far. He needs 4*59 so, how many points short is he?
November 17, 2016

Maths
Check with "Ed" below ...
November 17, 2016

Maths
h = 1 + 3t - 4.9t^2 You forgot about gravity
November 17, 2016

Maths
h - 4.9 * 1.5^2 = 0 v = -9.8t
November 17, 2016

Math
try here: http://davidmlane.com/hyperstat/z_table.html
November 17, 2016

Geometry
also, 19x-11 = 10x+7
November 17, 2016

maths
ok, now what?
November 17, 2016

math
by, not bye 29+16/9 = 30 7/9 I assume you meant (28+16)/9 = 45/9 = 5 Online, parentheses make a big difference!
November 17, 2016

math
Looks like a good unit to study, all right. Do you have any specific questions that are causing you difficulties? Do not expect someone here to provide you with all the answers...
November 17, 2016

Scale Math HELP!!!!!!!!!!
1.29 * 6.5 * (how many sides?)
November 17, 2016

Fizik
All your numbers are missing, but just find the net force and then use F = ma v = at s = 1/2 at^2
November 17, 2016

Tod
input your data here for the solution, as well as a graph of the region: http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html
November 17, 2016

Math grade 6, four operations
a+b+c = 75 a-28+19 = b+28-24 = c+24-19 or a+b+c = 75 a-9 = b+4 a-9 = c+5
November 17, 2016

math
the image is the same distance above the line y = -2 as it was below it to start. So, y -> -2+(-2-y) = -2+(y+4) = y+2 (-1,-3) -> (-1,-1)
November 17, 2016

math
14/16 = 7/8 = 35/40 1/5 = 8/40 now just add them up
November 17, 2016

Maths
500,000 + .05*1000,000 + .125*(1,200,000x-1,000,000) = 1,400,000 Too many zeros! Let's knock of 000,000 and we have (in millions) 0.5 + .05*1 + .125(1.2x-1) = 1.4 Better check my numbers. I get x = 6.5 ...
November 17, 2016

math
since the numerators are all the same, larger denominators means smaller numbers.
November 17, 2016

Math
ok
November 17, 2016

Integral Calculus
Looks to me like an = (-1)^(n-1) (n+1)!/4^(n-1)
November 17, 2016

math
5(a+4d) = 12(a+11d) 5a+20d = 12a+132d 7a = -112d a = -16d so, what is the 17th term?
November 17, 2016

Math (Slope of inverse tangent line)
correct
November 17, 2016

Morales
black: x(x+8) green: (x+3)(x+8) (x+3)(x+8) = x(x+8)+39
November 16, 2016

mathematics
8m+4n=12 3m+4n=2 subtract to get 5m = 10 ...
November 16, 2016

Math
I assume you meant interior diagonal x^2+2x+1 = (x+1)^2 So, each edge of the cube has length (x+1). For a cube of side length s, the main diagonal has length s?3, since the diagonal on a face is s?2. the main diagonal is ?(2s^2+1) = s?3 So, for this cube, the main diagonal has...
November 16, 2016

Algebra
5918*1.026^t = 11000000
November 16, 2016

Math
of course it exists. It's just the difference of two polynomials, so it's another polynomial. (f-g)(3) = f(3)-g(3) Now just plug in their values and simplify.
November 16, 2016

Algebra
since the roots come in conjugate pairs, y = (x+?3)(x-?3)(x-4i)(x+4i) = (x^2-3)(x^2+16) ...
November 16, 2016

chemisty
??
November 16, 2016

Differential calculus
see related questions below.
November 16, 2016

Algebra
not even close. See other post(s) on this problem.
November 16, 2016

Math
3a-4 = 5 3a < 9 a < 3 And that's "explain" not "expiation," which is something else entirely! (and not even a verb)
November 16, 2016

Math
(n)/(-3)+5>4 (n)/(-3)+1 > 0 1 > -n/(-3) 1 > n/3 3 > n or, n < 3
November 16, 2016

Physics
no, it is just the 3 meter part that is submerged. If it sinks, then the displaced water has the same volume as the object.
November 16, 2016

Math
must be polar bears.
November 16, 2016

math
each gets 1/4 of the candy! But I think you are asking how much of the original candy bar each person gets. That would of course be 1/4 * 2/3 Make sure you ask what it is you want to know.
November 16, 2016

math
in an equilateral triangle, the altitudes are the medians. So, the radius of the circle is 2/3 of the length of each altitude. ...
November 16, 2016

math
As I said earlier, http://www.jiskha.com/display.cgi?id=1479327393
November 16, 2016

Geometry
42
November 16, 2016

math
You are correct. I calculated using 2/3 of the projection of the median, which is wrong. I'll think on it some more. You do the same...
November 16, 2016

math
since the centroid is 2/3 of the way from each vertex to the opposite side, the projections on the sides are 2/3 the length of the sides. Their sum is thus 2/3 of the perimeter of ABC = 8
November 16, 2016

math
CDE is a 30-60-90 right triangle with ?C=30, so DE = 15.
November 16, 2016

math
better this time. B is correct
November 16, 2016

Algebra
If you went from 9|9-8x|=2x+3 to 8x=2x-6 you certainly did not divide by 9 (on BOTH sides)! All absolute-value problems have two possibilities. First, 9(9-8x)=2x+3 81-72x = 2x+3 78 = 74x x = 39/37 Second, 9(9-8x) = -(2x+3) 81-72x = -2x-3 70x = 84 x = 6/5
November 16, 2016

Algebra
|-4(-2)-8| + |-1-(-2)^2| + 2(-2)^3 |-4(-2)-8| + |-1-4| + 2(-8) |8-8| + |-1-4| - 16 0+5-16 -11
November 16, 2016

Math
no. 5:9 = ratio of squares:total squares:circles = 5:4
November 16, 2016

Math - OK
Huh. CDAC is correct. Don't know why I said otherwise. My bad. Sorry.
November 16, 2016

Math
NO stop guessing and do the math! I even gave you the numbers!
November 16, 2016

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