1.已知函数发f(x)=asinx+btanx+1满足f(5)=7,则f(-5)的值为( ）

1.f(x)=asinx+btanx+1
=> f(x) - 1 = asinx + btanx
令h（x）= f(x) - 1
h(-x) = a(sin(-x))+ b(tan(-x))
= -asinx - btanx
= - h(x)
=> h(-5)= f(-5) - 1 (1)
h(-5)= -h(5) = - (f(5)-1) = -(7 - 1)= -6 (2)
(1)(2) => f(-5) = -5
2.f(sin30度) = f(cos60度)= cos （3*60度）=cos 180度 = -1