Solving L.H.S of the equation:
⇒1−cosAsinA×cosAsinA⇒cosA(1−cosA)sin2A By formula, sin2A=1−cos2A⇒cosA(1−cosA)1−cos2A⇒cosA(1−cosA)(1+cosA)(1−cosA)⇒cosA(1+cosA)⇒cosA1+cosAcosA⇒secA+1.
Since, L.H.S. = R.H.S.
Hence, proved that (1−cosAsinA×tanA)=1+secA.