If $x + \frac{1}{x} = 2\,\,\cos \,\,\theta $, then ${x^n} + \frac{1}{{{x^n}}}$ is equal to

$\sin \,\,\left( {2\,n\theta } \right)$

$\cos \,\,\left( {2\,n\theta } \right)$

JEE MATHEMATICS MCQ: MULTIPLE AND SUBMULTIPLE ANGLES

1 Easy

1 of 1

Application +4 | -1

x + \frac{1}{x} = 2\,\,\cos \,\,\theta

, then

{x^n} + \frac{1}{{{x^n}}}

is equal to

View answer and explanation

Correct option: B

2\,\,\cos \,\,n\theta

Option B (

2\,\cos \,n\theta

) is correct because if

x + \frac{1}{x} = 2\,\cos \theta

, then

{x^n} + \frac{1}{{{x^n}}} = 2\,\cos \,n\theta

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