show that

arccot(2)+arccot(8)+arccot(18)+arccot(32)+...........=∏/4

THE GENERAL TERM OF THE SERIES AT L.H.S IS
arccot(2n²)which forms an identity with arccot(2n-1)-arccot(2n+1) ie

arccot(2n²)= arccot(2n-1) - arccot(2n+1)

Now putting n = 1 to infinity and then adding we can get

arccot(2)+arccot(8)+arccot(18)+arccot(32)+ .....= arccot(1) = pi/4

Thanks for the solution, Mr dk_ch