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Question : 145 of 160
Marks:
+1,
-0
Solution:
Given,
x=cos‌θ,y=sin‌5θ‌=−sin‌θ,‌=5‌cos‌5‌θ ‌∴‌‌‌=‌=−‌‌⇒‌‌‌=‌(‌)=‌(‌)⋅‌‌=‌(‌| −5‌cos‌5‌θ |
| sin‌θ |
)⋅‌‌=(‌| sin‌θsin‌5θ⋅25+5‌cos‌5‌θ‌cos‌θ |
| sin‌2θ |
)⋅‌‌=−‌−‌| 5‌cos‌5‌θ‌cos‌θ |
| sin‌3θ |
Now,
‌(1−x2)‌−x‌=‌(1−cos2θ)(‌−‌| 5‌cos‌5‌θ‌cos‌θ |
| sin‌3θ |
)‌−cos‌θ(‌| −5‌cos‌5‌θ |
| sin‌θ |
)=‌sin‌2θ(‌−‌| 5‌cos‌θ‌cos‌5‌θ |
| sin‌3θ |
)=‌−25sin‌5θ−‌| 5‌cos‌θ‌cos‌5‌θ |
| sin‌θ |
=‌−25sin‌5θ=‌−25y
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