a=r.cosx, find tan(X/2)

tan(2x) = 2tanx / 1 - (tan^2 (x))using this tanx = 2 tan (x/2) / (1- tan^2 x/2)assume tan(x/2) = tyou will get tanx = 2t/ 1-(t^2)find secx next then find cosx, then substitute cosx value, you will get answer

I enrolled ibps unlimited but still now it can't be access what i do?😡

You have already have access to the package you enrolled for. just login and take the mocks. go to my packages if you need direct links. https://cracku.in/profile/mypackages