只能用于三角形中.根据正弦定理sinA/a = sinB/b = sinC/c = k,若a = b,即Δ是等腰Δ则sinA/a = sinB/b = sinA/a = sinB/a ==> sinA = sinB你可能会想到sinB = sin(180 - B)°A + B + C = 180°A + 180° - B + C = 1...