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Let P={theta:sintheta-costheta=sqrt2cos...

Let `P={theta:sintheta-costheta=sqrt2cos theta}and Q={theta:sintheta+costheta=sqrt2sintheta}` be two ses. Then,

A

`Q notinP`

B

`P notinQ`

C

`P sub Q and Q-P ne phi`

D

`P=Q`

Text Solution

Verified by Experts

The correct Answer is:
D

Let Q `in` P. Then,
`thetainPhArrsin theta-costheta=sqrt2costheta`
`hArr1-2sinthetacostheta=2cos^(2)theta`
`hArr2 sin thetacos theta=2 cos^(2)theta`
hArr`1+2sin thetacos theta=2-2 cos^(2)theta`
`hArr(sin theta+cos theta)^(2)=2 sin ^(2)theta`
`hArr sintheta+cos theta=sqrt2sintheta`
`hArrtheta in Q.`
hence, `P =Q.`
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