Answer
See below.
Work Step by Step
1. $sin(x+h)=sin(x)cos(h)+cos(x)sin(h)$
2. $\frac{f(x_h)-f(x)}{h}=\frac{sin(x)cos(h)+cos(x)sin(h)-sin(x)}{h}
=\frac{cos(x)sin(h)-sin(x)+sin(x)cos(h)}{h}
=\frac{cos(x)sin(h)-sin(x)(1-cos(h))}{h}
=\frac{cos(x)sin(h)}{h}-\frac{sin(x)(1-cos(h))}{h}$
