## Content

- inverse equation
- polynomial equation
- Algebra_equation
- system of equations
- Diophantine equation
- congruence equation
- Modulus equation
- Probability_equation
- recurrence_equation
- functional_equation
- Inequalities
- differential equation
- fractional differential equation
- system of differential equations
- partial differental equation
- integral equation
- fractional integral equation
- differential integral equation
- test solution

- list()
- vector
- and

- Interactive plot 互动制图
- parametric plot, polar plot
- solve equation graphically
- dynamic plot 制图 with tangentplot
- area plot with integral
- complex plot
- Geometry 几何

- surface in 3D with plot3D
- contour in 3D with contour3D
- wireframe in 3D with wirefram3D
- complex function in 3D with complex3D
- a line in 3D with parametric3D
- a column in 3D with parametric3D
- the 4-dimensional object (x,y,z,t) in 3D with implicit3D

big1234567890123456789

input mod(3,2) for 3 mod 2

### Complex 复数

Complex( 1,2) number is special vector, i.e. the 2-dimentional vector, so it can be operated and plotted as vector.complex(1,2) = 1+2i

polar(1,45degree)

polard(1,45)

2cis(45degree)

#### Convert to complex( )

convert(1-2i to complex) = tocomplex(1-2i)

tocomplex(polar(1,45degree))

convert 1-i to polar = topolar(1-i)

topolard(1-i)

### Numerical approximations

n(polar(2,45degree))

n( sin(pi/4) )

n( sin(30 degree) )

n( sin(0.5,1) )

n( sin(1)^0.5 )