If `cos theta+cos phi=a` and `sin theta - sin phi=b`, then: `2cos(thet – InterviewSolution

1.	If `cos theta+cos phi=a` and `sin theta - sin phi=b`, then: `2cos(theta + phi)`=A. `a^2-b^2-2`B. `a^2-b^2+2`C. `a^2+b^2+2`D. `a^2+b^2-2`
Answer» Correct Answer - D

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