f（x）=sinx/4+cosx/4为什么等于根号2（x/4+π/4)

f（x）=sinx/4+cosx/4=√2[sin(x/4)（√2）/2+cos(x/4)(√2)/2]=√2[sin(x/4)cos(π/4)+cos(x/4)sin(π/4)]=√2sin(x/4+π/4)这种题目呢,就是凑成m（sinxcosy+cosx+siny）的形式如果f（x）=asinx+bcosx那么m=√（a^2...