Question

If cotA=7/8, find (1/sin A) (1/sinA)÷(1+cosA) (1-cosA).

Answer 1

I think in the numerator it is (1+sin A)(1-sin A)
because it is a common question with same value of cotA given in the question in manu text books and the answer of that question is below
please reffer

(1+sinA)(1-sinA)/(1+cosA)(1-cosA)
(a+b)(a-b)=a^2-b^2
so
1-sin^2(A)/1-cos^2(A)
because 1-sin^2A=cos^2 A
1-cos^2A=sin^2A
so

cos^2(A)/sin^2(A)
=cot^2(A)
=49/64