Answer:
A
Step-by-step explanation:
Check the solution by substituting x = [tex]\frac{\pi }{2}[/tex] into the left side of the equation
2sin²x - sinx - 1
= 2sin²([tex]\frac{\pi }{2}[/tex] ) - sin ([tex]\frac{\pi }{2}[/tex] ) - 1
= 2(1)² - 1 - 1
= 2 - 1 - 1
= 0
= right side
[tex]\frac{\pi }{2}[/tex] is therefore a solution to the equation
