For the first one, use the property
and then use tan(A-B) = (tan A- tan B) / (1+tan A tan B)
1. \int_{0}^{\pi /4}{ln(1+tant) dt}
2. \int (x.e^t^a^n^^^-^^^1^x)dx / (\sqrt{1+x^2})
For the first one, use the property
and then use tan(A-B) = (tan A- tan B) / (1+tan A tan B)