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प्रश्न
Prove that `( sintheta - 2 sin ^3 theta ) = ( 2 cos ^3 theta - cos theta) tan theta`
उत्तर
RHS = `(2 cos^3 theta - cos theta) tan theta`
=`(2 cos^2 theta - 1) cos theta xx sin theta/ cos theta`
=`[2(1- sin^2 theta ) -1] sin theta`
=` (2-2 sin^2 theta -1 ) sin theta`
=` (1-2 sin^2 theta ) sin theta`
=`( sin theta -2 sin^3 theta )`
=LHS
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Solution:
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∴ 1 + tan2 θ = `(25/7)^square`
∴ tan2 θ = `625/49 - square`
= `(625 - 49)/49`
= `square/49`
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