已知f(x)为奇函数,g(x)="f(x)+9, " g(-2)=3,则f(2)=_________.
5.已知π<α<2π,cos(α-7π)=-3/5,则sin(3π+α)的值为________
已知,则=___________________
已知函数其中都是非零实数,且满足,则=___________
=.