Prove that sin A (1 + tan A) + cos A (1 + cot A) = sec A + cosec A
LHS = sinA(1 + tan A) + cosA(1 + cot A)
= sin A (1 + sinAcosA) + cos A (1 + cosAsinA)
= sin A (cosA+sinAcosA) + cos A (sinA+cosAsinA)
= sin2A(cosA+sinA)+cos2A(sinA+cosA)cosAsinA
= (cosA)cosAsinA + sinAcosAsinA
= 1sinA + 1cosA
= cosecA + secA(RHS)