Evaluate of each of the following integrals (1-15): `int_(-a)^a1/(1+"a"^x)"d"x ,"a">0`

Evaluate each of the following integral: int_(-1)^1x|x|dx

Evaluate of each of the following integrals (1-15): int_0^(2pi)"log"(secx+tanx) dx

Evaluate each of the following integral: int_2^3 1/x dx

Evaluate of each of the following integral: int_(-pi//3)^(pi//3)1/(1+e^x)dx

Evaluate each of the following integral: int_(-2)^1(|x|)/x dx

Evaluate each of the following integral: int_-1^1 1/(x^2+1)dx

Evaluate each of the following integral: int_0^1(2x)/(1+x^2)dx

Evaluate of each of the following integrals (1-15): int_(-pi//4)^(pi//4)(x^(11)-3 x^9+5x^7-x^5+1)/(cos^2x)dx

Evaluate each of the following integral: int_0^1x\ e^x^2dx

Evaluate of each of the following integral: int_(-pi//2)^(pi//2)(cos^2x)/(1+e^x)dx