根号1-2sin/2cosx/2+根号1+2sin

1个回答

=√{[sin(x/2)]^2+[cos(x/2)]^2-2sin(x/2)cos(x/2)}+√{[sin(x/2)]^2+[cos(x/2)]^2+2sin(x/2)cos(x/2)}
=√{[sin(x/2)-cos(x/2)]^2}+√{[sin(x/2)+cos(x/2)]^2}
∵0