f(x)=(e^x)cos xf'(x) = (e^x) * (cos x)' + (e^x)' * cos x = -e^x * sin x + e^x * cos xf'(0) b = -e^0 * sin 0 + e^0 * cos 0 = -1 *0 + 1 *1 = 1函数图像在（0,f(0)）处的切线的斜率k=1斜率角=arc tan 1 = 45°...