(sec A + tan A)(1 β sin A)
We write everything in terms of sin A and cos A
= (1/cosβ‘γ π΄γ +" " sinβ‘γ π΄γ/cosβ‘γ π΄γ ) (1 β sin A)
= ((1 +γ sinγβ‘γ π΄γ)/cosβ‘γ π΄γ )(1 β sin A)
= ((1 +γ sinγβ‘γ π΄) (1 βγ sinγβ‘γ π΄)γ γ)/(cosβ‘ π΄ )
= ((12 βγ sin^2γβ‘γ π΄) γ)/( cosβ‘γ π΄γ )
= ((π βγ γπππγ^πγβ‘γ π¨) γ)/( πππβ‘γ π¨γ )
= cosβ‘γ2 π΄γ/( cosβ‘γ π΄γ )
= cos A
cos2 A + sin2 A = 1
cos2 A = 1 β sin2 A
β΄ 1 β sin2 A = cos2 A
So, the correct answer is (d)
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Davneet Singh
Davneet Singh is an IIT Kanpur graduate and has been teaching for 16+ years. At Teachoo, he breaks down Maths, Science and Computer Science into simple steps so students understand concepts deeply and score with confidence.
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