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If cos 3x+sin (2x-(7pi)/6)=-2, then x is...

If `cos 3x+sin (2x-(7pi)/6)=-2`, then x is equal to `(k in Z)`

A

`pi/3 (6k+1)`

B

`pi/3 (6k-1)`

C

`pi/3 (2k+1)`

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
D
`cos 3x+sin (2x-(7 pi)/6)=-2`
`:. Cos 3x=-1` and `sin (2x -(7pi)/6)=-1`
or `3x=(2n+1) pi and 2x-(7pi)/6=-pi/2+2 m pi , m, n in Z`
or `x=(2n pi)/3+pi/3 and x=mpi+pi/3`
or `x=2 kpi +pi/3, k in Z`.
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CENGAGE ENGLISH-TRIGONOMETRIC EQUATIONS-Exercises (Single Correct Answer Type)
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