若f(x)在[0,π]上连续,∫(0,π)f(x)cos(x)dx=∫(0,π)f(x)sin(x)dx=0 则存在a,b∈0,π,使得f(a)=f(b)=0
证明：若f(x)在[0,π]上连续,且
∫(0,π)f(x)cos(x)dx=∫(0,π)f(x)sin(x)dx=0
则存在0