# Having trouble with differential and linear approximation

1. Aug 6, 2012

### Cleowen

f(x)=x^3/2 with x=4 and deltax=dx=0.1 calculate deltay and dy

I got 0.4 for dy but its wrong, and i cant find deltay. plz help!!! thxs

2. Aug 6, 2012

### LCKurtz

In your post, do you mean $x\sqrt{x}$ or $\dfrac{x^3}{2}$ by x^3/2?