If cos theta - sin theta = root 2 sin theta , then what is the value of cos theta + sin theta ?
- root 2 cos (theta /2)
- (cosec theta) /2
- sin theta
- cos theta
Answer :- cos theta = root2 sin theta + sin theta
=> cos theta = sin theta ( root 2 + 1 )
=> cos theta = sin theta ( root 2 +1) (root 2 -1 ) / (root 2 -1 )
=> cos theta = sin theta [ (root 2)^2 - 1] / root2 -1
=> costheta (root 2 -1) = sin theta (2-1)
=> root 2 costheta - cos theta = sintheta
=> root 2 costheta = sin theta + cos theta -----ans
But there is no option .
- root 2 cos (theta /2)
- (cosec theta) /2
- sin theta
- cos theta
Asked by sucharitasahoo1 | 26th Dec, 2017, 05:46: PM
Expert Answer:
Your steps are correct. Check options again.
Answered by Sneha shidid | 27th Dec, 2017, 11:22: AM
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