sin²x+cos²x = 1(sinx+cosx)² =sin²x+cos²x +2sinxcosx = 47/25所以2sinxcosx = 22/25sinxcosx = 12/25 (解到这其实能猜出来是3/5 和 4/5)(√sinx + √cosx)² = sinx+cosx +2√(sin...