Q20 of 123 Page 9

Mark the Correct alternative in the following:

The value of is


Given expression is


[using the identity sin2 x + cos2 x = 1]




[using the formula a2 + b2 = (a + b)2 – 2ab]



[ using the sum of angle formula ]




[Using the identity cos (A+B) – cos (A-B) = -2sinAsinB ]





[multiplying and dividing the term cos2 x with 2]





[using the cos 2θ = 2cos2 θ – 1]




Hence the answer is option A.

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