# Math Help - Please need to finish homework

1. ## Please need to finish homework

1)Evaluate dy/dt for the function at the point xy^2 = 4 : dx/dt = -5, x= 4 , y = 1

2) Find the area bounded by the given curves.
y = x^3 , y = 4x

THANKS

2. 1. What are we supposed to do with this? Also, where does t fit in? You never specified anything about it.

2. If you make a quick sketch of the graph, you'll see that there are two regions in which they are bounded: from -2 to 0 (where y = x^3 is bigger than y = 4x) and from 0 to 2 (where y = 4x is bigger than y = x^3).

So, the areas bounded by both curves: $A = \int_{-2}^{0} \left(x^{3} - 4x\right)dx + \int_{0}^{2} \left(4x - x^{3}\right)dx$

3. ## my mistake

Evaluate dy/dt for the function at the point xy^2 = 4 : dx/dt = -5, x= 4, y=1

4. Originally Posted by ArmiAldi
Evaluate dy/dt for the function at the point xy^2 = 4 : dx/dt = -5, x= 4, y=1
Use implicit differentiation, and then substitute. Is there a particular part of the problem that you are having trouble with?