Question

@Michele_Laino

Answer 1

here I am!

Answer 2

ok! you have to calculate the first derivative of f(x)

Answer 3

do you know how to calculate df/dx?

Answer 4

ok! then write it, please!

Answer 5

\[\frac{ df }{ dx }=2+4....\]
please complete!

Answer 6

\[\frac{ df }{ dx }=2+4 \cos(4x)\]
are you agree?

Answer 7

@wade123

Answer 8

now set 2+4 cos(4x)=0
and simplify that expression, please. You have to get a trigonometric equation, please write it

Answer 9

here it is:\[\cos(4x)=-\frac{ 1 }{ 2 }\]
are you agree?

Answer 10

do you know how to solve it, please?

Answer 11

thisa is the situation of our equation