>>893
A=∫[-π/2,π/2] (cosx)^(2) / (2^(x) +1) dx
B=∫[-π/2,π/2] (cosx)^(2) / (2^(-x) +1) dx
C=A+B=∫[-π/2,π/2] (cosx)^(2) dx
A=B