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प्रश्न
Write the value of `sin theta cos ( 90° - theta )+ cos theta sin ( 90° - theta )`.
उत्तर
`sin theta cos theta (90° - theta ) + cos theta sin ( 90° - theta)`
= ` sin theta sin theta + cos theta cos theta `
=` sin^2 theta + cos^2 theta `
= 1
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Activity:
L.H.S = `square`
= `cos^2theta xx square .....[1 + tan^2theta = square]`
= `(cos theta xx square)^2`
= 12
= 1
= R.H.S
(tan θ + 2)(2 tan θ + 1) = 5 tan θ + sec2θ.
