Formulas for Differentiation of Trigonometric Functions[edit | edit source]
In the following formulas the angle u is supposed to be expressed in circular measure.






Proof for the derivative of 
Let
,
then
;
therefore
;
In Trigonometry,
If we substitute
and
,
we have
Hence
When
approaches zero,
likewise approaches zero, and as
is in circular measure, the limit of
Hence
Proof for 
Proof for 
Since 

Proof for 


