Trigonometry

How do I solve these?

1) 2sinxcosx-cosx=0
2) cos^2(x)-0.5cosx=0
3) 6sin^2(x)-5sinx+1=0
4) tan^2(x)+tanx-12=0

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  1. Factor them and set each of the factors equal to zero. Examples:
    (1) cos x(2 sinx -1) = 0
    cos x = 0 or sin x = 0.5
    x = pi/2, 3 pi/2; pi/6, 5 pi/6
    (4) (tanx -3)(tanx +4) = 0
    x = tan^-1 (1/3) or tan^-1(-1/4)

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  2. My answers above are in radians. You can easily convert them to degrees, if that is what they want.

    pi/2 radians it 90 degrees, etc

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