Calculate arctan12 arctan13 please show stepsSolutionarctan

Calculate

arctan(1/2) + arctan(1/3)

please show steps

Solution

arctan(1/2) + arctan(1/3)

arctanA +arctanB = arc{ (A +B)/( 1 -tanA*tanB)

In our case A = 1/2 and B = 1/3

So,arctan(1/2) + arctan(1/3) = arc{ (1/2+1/3)/( 1-1/2*1/3)

= arctan{ 5/6/( 5/6) }

=arctan 1

=pi/4