Question

Find the points on local extrema of function of f(x) = cos4x

Answer 1

Answer:

Step-by-step explanation:

We have to use the concept of differentiation here. f(x)= cos4x

d(cos4x)/dx= -4sin4x

Now we equate this -4sin4x=0

sin4x=0

4x=0, pi

x=0, pi/4

Now we take double differentiation of cos4x which is equal to -14cos4x.

Now if we put x=o and pi/4 here, we will find that at x=0, value is -14 and at x=pi/4 value is 14. Hence local extrema is at point x=o.

Therefore by using differentiation and double differentiation we find the local maxima and minima of a function.