1f(x)=2sinx乘cosx+2cos²x-1 =sin2x+cos2x =√2(√2/2sin2x+√2/2cos2x) =√2sin(2x+π/4)f(x)最大值为√22∵点p(-3,4)在角α的终点上 x=-3,y=4,r=5∴cosa=x/r=-3/5f(a+π/8)=√2sin[2(a+π/8)+π/4] =√2sin(2a+π/2)=√2cos2a=√2(2cos²a-1)=√2(2*9/25-1)=7√2/25