(1)/(21*(1)/((e^(x)-1)))" If int: Put "e^(x)=1}

Let f(x) = (e^(x)+1)/(e^(x)-1) and int_0^(1)( (e^(x)+1)/(e^(x)-1)) x dx = lambda , then int_(-1)^(1) t f(t) dt =

int(1)/(e^(x)+e^(-x))dx

int(e^(2x)+1)/(e^(2x)-1)dx=

int (e^(x)-1)/(e^(x)+1) dx =

int e^(x)/(e^(x)+1) dx =

int(1)/((e^(x)-1)(1-e^(-x)))dx

int_(0)^(1) (1)/(e^(x) +e^(-x)) dx

int_(0)^(1)(1)/(e^(x)+e^(-x))dx=

int_(0)^(1)(1)/(e^(x)+e^(-x))dx=

int (dx)/((1+e^x)(1+e^(-x)))=