Posted by **Freddy** on Monday, February 27, 2012 at 6:59pm.

Please check this for me:

the lenght l, width w, & height h of a box change with time. At a certain instant the dimensions are l=1m & w=h=2m. L and W are increasing at a rate of 2m/sec while H is decreasing at a rate of 2m/sec. At that instant, find the rate at which the surface area is changing.

Heres what I got:

We want the derivative of surface area with respect to t (ds/dt)...

ds/dt= 2y*dx/dt + 2x*dy/dt + 2z*dy/dt+ 2y*dz/dt + 2x*dz/dt + 2z*dx/dt

=2(2m)(-3) + 2(1m)(2) + 2(2m)(2)+ 2(2m)(2)+ 2(1m)(2)+2(2m)(-3)

=-12m+4m+8m+8m+4m+12m

=-24m+24m

=O m^2/sec

Is this right??

## Answer this Question

## Related Questions

- calc 3 - The length script l, width w, and height h of a box change with time. ...
- Calculus - Let V be the volume of a right circular cone having height h and ...
- algebra - a cardboard box which has a volume of 60 cubic inches and has the ...
- calculus - A recatangle has constant area of 200 square meters and its lenght L ...
- Calculus - Assume the dimensions of a rectangle are continuously changing in a ...
- calculus - At a certain instant of time, the sides of the cube are 3 in. long ...
- MATH!! - carl has a box with a length width and height of 12 inches. she needs a...
- algebra - carl has a box with a length width and height of 12 inches. she needs ...
- math - carl has a box with a length width and height of 12 inches. she needs a ...
- 5th grade math - Im confused please help thank you To find the volume of a box, ...

More Related Questions