I haven't done calculus level math in a long time, and this question has got me stumped ( Read more... )

Hi! So this question is on my midterm review and I'm not quite sure how to solve it.

Find the points on the surface xy3
+z2=4 that are closest to the origin.

Here's what I have so far:
Origin means (0,0,0)
So: D=√x2+y2+z2
D2= x2+y2+z2
and
z2=4-xy3
f(x,y)= x2+y2+4-xy3

fx= 2x-y3
fy= 2y-3xy2
fxx= 2
fyy= 2-6xy
fxy= -3y2Working with these two first, ( Read more... )

A rectangle is inscribed in a circle of radius 5 inches. If the length of the rectangle is decreasing at the rate of 2 inches per second, how fast is the area changing when the length is 6 inches ( Read more... )

I need some help with double integrals. I have the following homework problem:

Let D be the region of the plane bounded by the two hyperbolas xy = 1 and xy = 4, and by the two cubics y = x3 and y = 5x3. Evaluate over D ∫∫ [(x2 + y2)/x2]dx dy ( Read more... )

Dear math_help ( Read more... )

I am having trouble finding my limits of integration. First of all, I am trying to find the volume of a solid that has the cross sections in the shape of equilateral triangles of a function.
My equation is x2 + y2 = e2, so on a graph it would make a circle shape, right?
I will find the volume by finding the integral of the equation of the area of ( Read more... )

There are some problems that I am correcting, but I don't really understand why I got them wrong. I would greatly appreciate some help! My work is under the cut. Thank you in advance!

( Read more... )

I am to determine if the function j(k)= tan|k| is differentiable... I tried to determine it graphically, but still wasn't sure, so I decided to try to find it algebraically, so I set it up like this ( Read more... )

My problem reads: At time t seconds an object is located at the point x(t) = R(t-sin(t)), y(t) = R(1-cos(t)), in feet.  At what time is the object traveling fastest?

I have the speed equation, but how do I determine when the object is traveling fastest?  Thanks for all the help in advance :)!

I'm taking a coding theory and cryptography course and don't quite know how to get M or d below. I know that n = n1 + n2.

1. Let C1 be a (n1, M, d1) q-ary code and C2 a (n2, M, d2) q-ary code. Assume that we have named the codewords:
C1 = {w1, w2,...,wM},
C2 = {v1, v2,...,vM}.
Define the new code C3 as the set of words wivi for i = i ( Read more... )