说明：  1.力的合成代码。输入任意两个力及其夹角，能够输出合成后的力的大小和方向。 2.等值线云图代码。三维图形等高线云图的绘制及其任意确定二维视角云图的绘制 3.求根代码。用fzero函数对超越方程求数值根 4.求导代码。用diff函数对sin（x）求导的数值方法 5.正负点电荷电场等势线代码。正负点电荷的电场等势线彩图
(1. The composition of forces of code.Enter any two force and Angle, can output after synthetic size and direction of the force. 2. The isoline chart code.3 d graphics contour chart drawing and any cloud image in the view of the 2 d drawing 3. Ask the root code.Using fzero function of transcendental equation and numerical root 4. The derivation of code.Using diff function of sin (x) derivation of the numerical method 5. Positive and negative point charge electric field equipotential lines of code.The positive and negative electric field of point charge equipotential line color map)