When a tangent line is horizontal?
Find all points on the graph of the function f(x) = 2sinx + sin²x at which the tangent line is horizontal.
I need help. I am stuck.
- ComoLv 71 month ago
f ' (x) = 2 cos x + 2 sin x cos x = 0
2 cos x ( 1 + sin x ) = 0
cos x = 0 , sin x = -1/2
x = π/2 , 3π/2 , x = 7π/6 , 11π/6_________ ± 2n π