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Let

f(x)=4e2x+1ex
  1. Find f′(x) and f″(x)

  2. Hence, find the minimum value of f, justifying that this is a minimum point.


Express f in the form

f(x)=4ex+e−x

in order to differentiate it


Remember that ln⁡(x) and ex are inverse to each other, which means

ln⁡(ex)=x

and

eln⁡(x)=x

You must use the second derivative test to determine the nature of the turning point.


Give your answer below