(xiii)(2sin theta*tan theta(1-tan theta)+2sin theta*sec^(2)theta)/((1+tan theta)^(2))=(2sin theta)/(1+tan theta)

(2 sin theta * tan theta (1- tan theta ) + 2 sin theta sec^(2) theta )/( (1+ tan theta)^(2))=

(2 sin theta * tan theta (1- tan theta ) + 2 sin theta sec^(2) theta )/( (1+ tan theta)^(2))= .......... A) (sin theta)/(1+ tan theta) B) (2 sin theta)/(1+ tan theta) C) (2 sin theta)/((1+ tan theta )^(2)) D) (sin theta)/((1+ tan theta)^(2))

(tan theta+sin theta)/(tan theta-sin theta)=(sec theta+1)/(sec theta-1)

cos theta(tan theta+2)(2tan theta+1)=2sec theta+5sin theta

cos theta(tan theta+2)(2tan theta+1)=2sec theta+5sin theta

cos theta(tan theta+2)(2tan theta+1)=2sec theta+5sin theta

(tan theta+sec theta-1)(tan theta+1+sec theta)=(2sin theta)/(1-sin theta)

(1+2sin theta+sin^(2)theta)/(cos^(2)theta)=(sec theta+tan theta)/(sec theta-tan theta)

prove that :(1-sin2 theta)/(1+sin2 theta)=((1-tan theta)/(1+tan theta))^(2)