If `tan 25^@ = x`, then `(tan155^@ - tan115^@)/(1+tan 155^@ tan115^@)` is equal to

If tan25^(@) = x , then (tan155^(@) - tan115^(@))/(1 + tan155^(@) tan115^(@)) equals :

If tan 25 ^@ =a then ( tan 155^@ - tan 115^2 )/( 1+tan 155^2 tan 115^@ ) is

If tan 25^(@) = a , prove that, (tan 155^(@) - tan 115^@)/(1 + tan 155^@ tan 115^@) = (1 - a^2)/(2a)

If : x = tan25^(@), "then": (tan 155^(@) - tan 115^(@))/(1 + tan 155^(@) * tan 115^(@))= A) (1-x^(2))/(2x) B) (1+x^(2))/(2x) C) (1+x^(2))/(1-x^(2)) D) (1-x^(2))/(1+x^(2))

tan25^@=a prove that (tan155^@-tan115^@)/(1+tan155^@.tan115^@)=(1-a^2)/(2a)

If tan 25^(@)=a , prove that (tan 155^(@)-tan115^(@))/(1+tan155^(@)tan115^(@))=(1-a^(2))/(2a) .

tan^(-1)(tan19) is equal to