[" (79) fuse anfigit for "],[qquad tan^(-1)a+tan^(-1)b=cos^(-1)(1-ab)/(sqrt((1+a^(2))(1+b^(2))))]

Prove that : tan^(-1) a - tan^(-1) b = cos ^(-1) [(1+ab)/(sqrt((1+a^(2))(1+b^(2))))]

Prove that : tan^(-1) a - tan^(-1) b = cos ^(-1) [(1+ab)/(sqrt((1+a^(2))(1+b^(2))))]

Prove that, tan^(-1)a+tan^(-1)b+tan^(-1)((1-a-b-ab)/(1+a+b-ab))=(pi)/(4) .

Prove that 2tan^(-1)sqrt((b)/(a))=cos^(-1)((a-b)/(a+b))

The expression (1)/(sqrt(2)){(sin tan^(-1)cos tan^(-1)t)/(cos tan^(-1)sin cot^(-1)sqrt(2)t)}*{sqrt((1+2t^(2))/(2+t^(2)))}

tan[tan^(-1)(1/(a+b))+tan^(-1)(b/(a^(2)+ab+1))]=

The value of tan^(-1)((sqrt(3))/(2))+tan^(-1)((1)/(sqrt(3))) is equal to a) tan^(-1)((5)/(sqrt(3))) b) tan^(-1)((2)/(sqrt(3))) c) tan^(-1)((1)/(2)) d) tan^(-1)((1)/(3sqrt(3)))

tan(A/2)=(sqrt((1-cos A)/(1+cos A)))

y = tan ^ (- 1) [sqrt ((ab) / (a + b)) (tan x) / (2)]

Prove that: tan[(pi)/(4)+(1)/(2) tan^(-1)((a)/(b))]+tan[(pi)/(4)-(1)/(2)tan^(-1)((a)/(b))]=(2sqrt(a^(2)+b^(2)))/(b)