1+sin2x+cos2x=1+sin(2x+π/4),为什么?_其他解答

1+sin2x+cos2x=1+sin(2x+π/4),
为什么?

人气：399 ℃　时间：2020-06-08 12:30:42

解答

1+sin2x+cos2x
=1+√2(sin2x*√2/2+cos2x*√2/2)
=1+√2(sin2xcosπ/4+cos2xsinπ/4)
=1+√2sin(2x+π/4)