# Homework Help: How do you find a dervative of this

1. Mar 22, 2008

### janemba

how do you find the derivative of this problem and what rule do you use

lim sin(pi+h)-Sin pi
h-> 0 h

2. Mar 22, 2008

### tiny-tim

… sinπ = 0 …

Hi janemba!

Do you mean $$\frac{sin(\pi + h) -sin\pi}{h}$$ ?

If so, remember that sinπ = 0, so it's just $$\frac{sin(\pi + h)}{h}\,.$$

Which is … ?

3. Mar 23, 2008

### janemba

yes but how did you got the answer

4. Mar 23, 2008

### rocomath

How do you expand:

$$sin(x+y)=???$$

Trig identity ...

5. Mar 23, 2008

### Gib Z

It's even simpler than that, take a look at a unit circle and think about what happens with every rotation of pi radians.