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InterviewSolution
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If `tanalpha=sqrta` where a is not a perfect square then which of the following is a rational numberA. `sin 2 alpha`B. `tan 2 alpha`C. `cos 2 alpha`D. none of these |
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Answer» Correct Answer - C We have, `sin2 alpha=(2tanalpha)/(1+tan^(2)alpha)=(2sqrta)/(1+a),` which is an irrational number `tan2alpha=(2 tanalpha)/(1-tan^(2)alpha)=(2sqrta)/(1-a),` which is an irrational number `cos 2 alpha=(1-tan^(2)alpha)/(a+tan^(2)alpha)=(1-a)/(1+a),` whihc is a rational number. |
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