That is a consequence of the Schwarz Bunyakovsky Inequality
(0∫1 f(x) g(x) dx)2 ≤ 0∫1 f2(x) dx 0∫1 g2(x) dx
Hence (0∫1√(1+x)(1+x3) dx)2 ≤ 0∫1 (1+x) dx 0∫1 1+x3 dx = 15/8
That is a consequence of the Schwarz Bunyakovsky Inequality
(0∫1 f(x) g(x) dx)2 ≤ 0∫1 f2(x) dx 0∫1 g2(x) dx
Hence (0∫1√(1+x)(1+x3) dx)2 ≤ 0∫1 (1+x) dx 0∫1 1+x3 dx = 15/8
good one dude.. i was thinking this one for a few minutes.. could not get a solution.. :)