let give f(x) =∫_0 ^(π/2) (dt/(1+x tant))
1) find a simple form of f(x)
2) calculate ∫_0 ^(π/2) ((tant)/((1+xtant)^2 ))dt
3)give the value of ∫_0 ^(π/2) ((tant)/((1+(√3) tant)^2 )) dt .
g is real function continue let
f(x)=∫_0 ^x sin(x−t)g(t)dt
1)prove that f^′ (x)= ∫_0 ^x cos(t−x)g(t)dt
2)prove that f is so<ution of the diff.equa.
y^(′′) +y =g(x)