# Differentiation

#### b521

z² = x² + y²

dx/dt = 2
dy/dt = 3

Find dz/dt when x = 5 and y = 12

I tried solving this problem but got very confused. Help would be much appreciated!

#### xxp9

2zdz/dt = 2xdx/dt + 2ydy/dt

#### pencil09

z² = x² + y²

dx/dt = 2
dy/dt = 3

Find dz/dt when x = 5 and y = 12

I tried solving this problem but got very confused. Help would be much appreciated!
$$\displaystyle z^2=x^2+y^2$$

$$\displaystyle \frac{d(z^2)}{dt}=\frac{d(x^2+y^2)}{dt}$$

$$\displaystyle \frac{d(z^2)}{dt}=\frac{d(x^2)}{dt}+\frac{d(y^2)}{dt}$$

can u continue from here....??

-- hope it'll help --

HallsofIvy