Trigonometry help pleasee

5. What is the smallest positive value for x where y = sin 2x reaches its maximum?
A. π/4
B. π
C. 3π/2
D. 2π
E. 5π/2

find amplitude then period.

Amp=1

period=pi

quarter period=pi/4


Add pi/4 till you get to pi


pi/4+pi4=2pi/4


2pi/4+pi/4=3pi/4

3pi/4+pi/4=4pi/4=pi.


now use the points pi/4, 2pi/4, 3pi/4, pi, as your x values. The first time you will get a maximum which is 1 is at pi/4.


The smallest vale when sin2x reaches its maxium is pi/4.

sin ɵ function reaches maximum positive when ɵ = л/2
Here ɵ = 2x
For maximum y, 2x = л/2
x = л/4

Answer is A