Derivatives 
What they are and how do we find them?
Definition of a Derivative 
The instantaneous slope of a 
function/the slope of a 
function at a specific instant
Notations of Derivative of y=f(x) 
f’(x) 
y’ 
dy/dx 
d/dxf(x)
Numerical Derivative 
f’(a) = lim f(x)-f(a) 
x->a x-a 
f’(x) = lim f(x+h)-f(x) 
h->0 h
Finding a Derivative 
Tips and Tricks
Trigonometric Rules 
d/dxsin(x) = cos(x) 
d/dxcos(x) = -sin(x) 
d/dxtan(x) = sec2(x) 
d/dxsec(x) = sec(x)tan(x) 
d/dxcot(x) = -csc2(x) 
d/dxcsc(x) = -csc(x)cot(x)
Other Important Derivatives to Know 
d/dx ex = ex 
d/dx ax = (ax) ln(a) 
d/dx ln(x) = 1/x
Power Rule 
If f(x)=xn, 
then f’(x)=nxn-1.
Power Rule Examples 
f(x)=x3  f’(x)=3x2 
f(x)=x5  f’(x)=5x4
Product Rule 
If f(x)=gh, 
then f’(x)=g’h+h’g.
Product Rule Examples 
f(x) = x2sin(x)  f’(x) = 2xsin(x)+x2cos(x) 
f(x) = 3x3ex  f’(x) = 9x2ex+3x3ex
Quotient Rule 
If f(x)=u/v, then 
f’(x)=vu’-u’v 
v2.
Quotient Rule Examples 
f(x) = x2/sin(x)  f’(x) = sin(x)2x-x2cos(x) 
x4 
f(x) = sin(x)/ln(x)  f’(x) = ln(x)cos(x)-sin(x)*(1/x) 
(ln(x))2
Chain Rule 
If f(x)=g(h(x)), then 
f’(x)=g’(h(x))*h’(x)
Chain Rule Examples 
f(x) = sin(ln(x))  f’(x) = cos(ln(x))*(1/x) 
f(x) = e(x^2)  e(x^2)*2x

Derivatives