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If un = 2cos n theta then u1un - u(n-1) ...

If `u_n = 2cos n theta` then `u_1u_n - u_(n-1)` is equal to

A

`u_(n +2)`

B

`u_(n+1)`

C

`u_2 u_(n+1)`

D

none of these

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A DAS GUPTA-Circular Functions, Identities -Exercise
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