Question

cos(3π/2 +x) cos(2π/ +x) { cot (3π/2 -x) + cot (2π+x) } = 1

Answer 1

cos(pie/2+pie+x)cosx ( cot(pie/2 +pie -x) +cotx) = sinx cosx( tanx+cotx) =sin^2x + cos^2x =1