Question

For what values of x in [0,2π] does the graph of f(x)=x+2sinx have a horizontal tangent?
List the values of x below.

Answer 1

I don't know how to set up the equation, that's what I was asking.

Answer 2

Find the first derivative, f'(x)
Solve f'(x)=0 (horizontal tangent occur when the slope is zero).
You can find x from here.

Answer 3

f'(x)=1+2Cos(x)
1+2Cos(x)=0
\(Cos(x)=\large\frac{-1} {2} \)
\(Cos^{-1} \large(\frac{-1} {2})=x\)
x=120 and 300

Answer 4

Did you follow?

Answer 5

I skipped out some steps but I am assuming you are familiar with trig

Answer 6

@Kalen Are u there?

Answer 7

Do u not follow?