Derivatives of Sums

Example:
C(t) = 6*(sin(t))2 - (e)2

The first thing to notice when finding the derivative of this function is that it is the sum of several terms, as shown in color below:

C(t) = ( 6*(sin(t))2 ) - ( (e)2 )

The Derivative Rule for Sums:

The derivative of a sum is the sum of the derivatives.
If
  z = ( f(x) + g(x) )
then the derivative of z is
  z' = ( f(x) + g(x) )'
    = f '(x) + g'(x)

So our example,

C(t) = ( 6*(sin(t))2 ) - ( (e)2 )
we can think of as
C(t) = f(t) - g(t)
So the derivative is
C '(t) = ( f(t) - g(t) )'
  = f '(t) - g '(t)  
  = ( 6*(sin(t))2) ' - ( (e)2) '  
and we just need to know each of the derivatives on the right-hand side of the equation. In this case these are
( 6*(sin(t))2 )' = 6*2*sin(t) cos(t) (by the rule for constant multiples, and the chain rule)
( (e)2 )' = 0 (by the derivative rule for constants)
so the finished derivative is
C '(t) = 6*2*sin(t) cos(t) - 0  
  = 12*sin(t) cos(t)
[]


additional explanation for the derivative of sums
see another derivative of sums example
practice gateway test
previous page
Page Generated: Wed Sep 23 04:26:13 2026
Comments to Gavin LaRose
glarose@umich.edu
©2001 Gavin LaRose, University of Michigan Math Dept.