r = 1；

parameter plot[{ r a-r Cos[a]，-r + r Sin[a]}，{a，-2 Pi，2 Pi}]

Just in case there is no mistake. Tested, copy it directly to Mathematica window and press Shift+Enter to run.

R can be assigned to any number with the same shape.

Note that "{a, -2π, 2π}" gives the range of parameters. The landlord can try to modify it.

In Mathematica, Pi stands for pi.

The default coordinate is the golden ratio. Add a command to adjust the scale, for example

r = 1；

parameter plot[{ r a-r Cos[a]，-r + r Sin[a]}，{

a，-2π，2π}，aspectation-& gt； 1]

The number after "AspectRatio" indicates the height-width ratio, and the larger it is, the slimmer it is.

Where do you want to draw the tangent? Just work out the parameter equation before drawing. If you don't tell me where to draw the tangent, I'll draw it for you.

Really lazy, forget it, help people to the end.

I will also help you calculate the tangent equation, so the following two are the graphs and tangent graphs you want.

fig 1:= parametericplot[{ a-Cos[a]，- 1+Sin[& lt； br & gta]}，{a，-2π，2π}，aspectation-& gt； 1];

f[a _]:= Plot[Cos[a]/( 1+Sin[a])(x-a+Cos[a])- 1+Sin[a]，{x，- 10， 10 }]；

Run these two formulas first. Then run the following formula to draw pictures and tangents, such as

Show[fig 1，f[2]]；

Is to draw a graph and the tangent at x=2 on a graph at the same time. You can adjust the value in square brackets after f by yourself to see the tangent of the point you want.