1.

`sin^(4) theta + cos^(4) theta` in terms of ` sin theta` is ______A. `2 sin^(4) theta -2 sin^(2) theta-1`B. `2 sin^(4) theta-2 sin^(2)theta+1`C. `2 sin^(4) theta + 2 sin^(2) theta-1`D. `2 sin^(4)theta-2 sin^(2)theta`

Answer» Correct Answer - B
(i) Use `(a+b)^(2)=a^(2)+b^(2)+2ab and cos^(2)theta=1-sin^(2) theta `.
(ii) Take `cos 4 theta ` as (1- sin^(2) theta)^(2)` and simplify.


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