Question

sin45-a=cos多少

Answer 1

首先，我们使用三角恒等式之一（cos(a - b) = cos(a)*cos(b) sin(a)*sin(b)）将cos转换为一个sin函数。具体来说，sin(45-a) = sin(45)*cos(a) - cos(45)*sin(a) = (1/√2)*cos(a) - (1/√2)*sin(a)。因此，cos(a) = (1/√2)*cos(a) (1/√2)*sin(a) sin(45)。接下来，我们根据sin(45) = cos(45) = 1/√2进行简化，得到：cos(a) = (1/√2)*cos(a) (1/√2)*sin(a) 1/√2。然后，我们可以从等式两侧减去(1/√2)*cos(a)，得到：cos(a) - (1/√2)*cos(a) = (1/√2)*sin(a) 1/√2，即(1/√2)*cos(a) = (1/√2)*sin(a) 1/√2. 最后，我们可以将两侧除以(1/√2)，得到：cos(a) = sin(a) √2/2.