[c*f(x)]'=c*f'(x)
[f(x)±g(x)]'=f'(x) ±g'(x)
[f(x)*g(x)]'=f'(x)g(x)+f(x)g'(x)
[f(x)/g(x)]'=[ f'(x)g(x)-f(x)g'(x)]/[g(x)]2
(f◦g)'(x)=f'(g(x))g'(x)