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Help me with soling trigonometry please

solve for 0≤ϴ≤360
3cos^2ϴ+5sinϴ-1=0
I got:
3(1-sin^2ϴ)+5sinϴ-1=0
2-3sin^2ϴ+5sinϴ=0
3sin^2ϴ-5sinϴ-2=0
3x^2-5x-2=0
(3x+1)(x-2) ------> (3sinϴ+1)(sinϴ-2)=0

3sinϴ+1=0
sinϴ=-1/3
sin-1(-1/3)=-19.47 (ans, but not in range)

sinϴ-2=0
sinϴ=2
sin-1(2)=None (ans)

how do i make this work?
with sin, you subtract your first answer from 180 (or pi if youre doing it in radians) then add 360 to all of the solutions
Use CAST/graph to generate other solutions. Use the periodicity of the trigonometric functions.

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