If θ ∈ [ − 2 π , 2 π ] , then the number of solutions of 2 2 cos 2 θ + ( 2 − 6 ) cos θ − 3 = 0 , is equal to:

Question

If θ ∈ [ − 2 π , 2 π ] , then the number of solutions of 2 2 ​ cos 2 θ + ( 2 − 6 ​ ) cos θ − 3 ​ = 0 , is equal to:

TestHub · Accepted Answer

​ 2 2 ​ cos 2 θ + 2 cos θ − 6 ​ cos θ − 3 ​ = 0 ( 2 cos θ − 3 ​ ) ( 2 ​ cos θ + 1 ) = 0 cos θ = 2 3 ​ ​ , 2 ​ − 1 ​ ​ Number of solution = 8

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