Question

(1-cosa) (1+cosa)/(1-sina) (1-sina) =tan2​

Answer 1

Solution:

LHS=

[(1-cosA)(1+cosA)]/[(1-sinA)(1+sinA)]

= (1²-cos²A)/(1-sin²A)

/* (a-b)(a+b) = a²-b² */

= sin²A/cos²A

/*

i) 1-cos²A = sin²A

ii) 1-sin²A = cos²A */

= tan²A

/* sinA/cosA = tanA */

= RHS

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