★ 您好,忄隹e习 习 很高兴可以为您解答问题 ★\x0d-----------------------------------------------------------------\x0d∵1+sinx=[sin(x/2)+cos(x/2)]^2,\x0d∴cosx=[cos(x/2)+sin(x/2)][cos(x/2)-sin(x/2)],两...