Question

Tan A - 1 / tan A + 1 × sin A + cos A / sin A - Cos A = 1

Answer 1

A = x
= (tanx - 1 : tanx + 1) x (sinx + cosx / sinx - cosx)
= (sinx/cosx-1 : sinx/cosx+1)x(sinx+cosx / sinx-cosx)
= ((sinx-cosx)/cosx : (sinx+cosx)/cosx) x (sinx+cosx / sinx-cosx)
= (sinx-cosx/cosx .x. cosx/sinx+cosx) x (sinx+cosx / sinx-cosx)
= (sinx-cosx/sinx+cosx) x (sinx+cosx / sinx-cosx)
→dicoret smua←
= 1