Ans)
You can integrate tanθ
write tanθ=sinθ/cosθ
so now, integral of tanθ.dθ=integral of sinθ/cosθ.dθ→1
put cosθ=t→2
there fore -sinθ.dθ=dt→3
put 2 and 3 in 1
so,the question becomes integral of tanθ.dθ=integral of -dt/t→4
=-log t +c → 5 [reason:dx/x=logx]
put 2 in 5,
=-log cosθ+C
where C is the integration constant