Question

[紧急求助,sinx+cosx怎么化简成,根2sin(x+派/4),辛苦

Answer 1

方法一:

y= asinx+bcosx=√(a^2+b^2)sin(x+arctanb/a)

所以y=sinx+cosx=√2sin(x+pi/4)

方法二:

sinx+cosx

=√2(cos45°sinx+sin45°cosx)

=√2sin(x+45°)

==√2sin(x+π/4)