solve the following equation

Question

Solve the following equation in the interval [0, 2  π]. 

Note: Give the answer as a multiple of π. Do not use decimal numbers. The answer should be a fraction or an integer. Note that π is already included in the answer so you just have to enter the appropriate multiple. E.g. if the answer is π/2 you should enter 1/2. If there is more than one answer enter them separated by commas.

2(sin⁡(t))^2−sin⁡(t)−1=0

t =   

Answer 1

u = sin t?

2u² - u - 1 = 0

Can you factor (Algebra 1), and Use Zero Product Rule (Algebra 2)