If a,b,c>0 then find value of tan^-1(√a(a+b+c)/bc)+tan^-1(√b(a+b+c)/ca)+tN^-1(√c(a+b+c)/ab).

The answer is b. Then shortcut to solving it is that we need to substitute value of theta as 30 degree.

Find the realtions of values of x,y,z. You will get x/2 = y√3/2 = z√3. Find all the terms in terms of x. Substitute in the given expression, find the answer and see which one of the options matches your answer. You will get the 4 marks very easily this way.