if `tan theta=4/9`
then `(1-tan^2theta)/(1+tan^2theta)`

(1+tan^2theta) sin^2theta

Prove that: tan4theta=(4t a ntheta(1-tan^2theta))/(1-6tan^2theta+tan^4theta)

If theta=30^@ , verify that: (i) cos2theta=(1-tan^2theta)/(1+tan^2theta) (ii) cos3theta=4cos^3theta-3costheta

Prove that : tan 4 theta = (4 tan theta - 4 tan^3 theta)/(1-6 tan^2 theta + tan^4 theta) .

Prove that (tan^2 (2theta)-tan^2 theta)/(1-tan^2 (2theta) tan^2 theta)=tan (3theta)tan theta

If theta=30^@ , verify that: (i) tan2theta=(2tantheta)/(1-tan^2theta) (ii) sin2theta=(2tantheta)/(1+tan^2theta)

Prove: tan (45^(@)+ theta ) = (1 + tan theta)/( 1- tan theta )

Prove: tan (45 ^(@) - theta ) =(1 - tan theta)/( 1 + tan theta)

If tantheta+1/(tantheta)=2 , find the value of tan^2theta+1/(tan^2theta)

Prove that (1+sin 2theta)/(1-sin 2theta) = ((1+tan theta)/(1-tan theta))^2