Derivatives of Sums

Example:
y = 2x + (3)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:

y = ( 2x ) + ( (3)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,

y = ( 2x ) + ( (3)2 )
we can think of as
y = f(x) + g(x)
So the derivative is
y ' = ( f(x) + g(x) )'
  = f '(x) + g '(x)  
  = ( 2x) ' + ( (3)2) '  
and we just need to know each of the derivatives on the right-hand side of the equation. In this case these are
( 2x )' = (ln(2))*2x (by the derivative rules for basic functions)
( (3)2 )' = 0 (by the derivative rule for constants)
so the finished derivative is
y ' = (ln(2))*2x + 0  
  = (ln(2))*2x
[]


additional explanation for the derivative of sums
see another derivative of sums example
practice gateway test
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glarose@umich.edu
©2001 Gavin LaRose, University of Michigan Math Dept.