已知直線的傾角為15度，求斜率。求計算方法！謝謝妳

=譚(45 -30歲)

=(tan 45-tan 30)/(1+tan 45 * tan 30)

=(1-√3/3)/(1+1*√3/3)

=(3-√3)/(3+√3)

=(3-√3)^2/(3+√3)(3-√3)

=(9-6√3+3)/6

=2-√3