x=(x2-x 1)t+x 1

y=(y2-y 1)t+y 1

z=(z2-z 1)t+z 1

Then the above two points are substituted into the above formula, and the specific parameter equation is obtained as follows:

x = t+ 1；

y = 2t+ 1；

z=3t+ 1 .

brief introduction

Generally speaking, in the plane rectangular coordinate system, if the coordinate x and y of any point on the curve is a function of a variable t.

And for each allowable value of t, the point (x, y) determined by the equations is on this curve, then this equation is called the parametric equation of the curve, and the variable T connecting the variables x and y is called the parametric variable, which is called the parameter for short. Relatively speaking, the equation that directly gives the point coordinate relationship is called the constant equation.