# Chain Rule Differentiation

1. Oct 16, 2005

### forevermoreOC

h = 3x^2.y^3
find dh/dt, if x=1, and y=2
Also, dx/dt = 0.2, dy/dt = 0.1

Any ideas where i should start in order to get this out?
Thanx

2. Oct 16, 2005

### Dr Transport

$$\frac{dh}{dt} = \sum_i \frac{dF}{dx_i}\frac{dx_i}{dt}$$, you have the expression for $$h$$ and the points at which to calculate the final answer.

3. Oct 17, 2005

### forevermoreOC

I dont understand that expression, can you simplify your explanation please

4. Oct 17, 2005

### HallsofIvy

Staff Emeritus
If x is a function of t, f(x)= x^2, what does the chain rule say
df/dt is?