My initial thought was to introduce a parameter and differentiate, but that approach didn't get me anywhere.
here's mine to the second:
put on the integral to see that is equal to
i claim the latter integral equals hence the original integral equals so in order to see that write the integral as
and put on the second one, then add them up and you'll see that the claimed integral achieve the aforesaid value, as required.
another solution for the first one:
we consider (1) then write it as and put on the second one then we get so when adding those we note that the integrand is actually so (1) equals
on the original integral was easy to show that it's equal to thus by (1) we conclude.