Exactly what that person said. Use sin x as a variable.
Replace with :
See how this looks like a quadratic? If you replaced with you would get
Solve the quadratic for y, plug back in for y, and solve for x.
Find all exact solutions on [0,2pi)
2(cos^2)x + 3sinx = 3
Someone said i had to use (cos^2)x + (sin^2)x = 1 and use sin x as a variable, but i do not understand what that means.
Can someone explain to me step by step?