Question

1+sin2A / cosA=cosA +sinA /cosA- sinA

Answer 1

Solution:

RHS =(cosA+sinA)/(cosA-sinA)

Multiply numerator and denominator by (cosA+sinA), we get

= (cosA+sinA)²/[cos²A-sin²A]

= (cos²A+sin²A+2sinAcosA)/cos2A

= (1+sin2A)/cos2A

/*

i) cos²A+sin²A = 1

ii) 2sinAcosA = sin2A

iii) cos²A-sin²A = cos2A

*/

= LHS

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