1.
f:[0,1]→[0,1]f:[0,1]\to[0,1] continuous, x2+f(x)2≤1x^2+f(x)^2\le1, ∫01f=π/4\int_0^1 f = \pi/4. Then ∫1/21/2f(x)1−x2dx\int_{1/2}^{1/\sqrt2}\frac{f(x)}{1-x^2}dx equals