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### Plot a circle.

Posted: **Fri Feb 23, 2018 3:44 pm**

by **henkoegema**

Can somebody tell me how to plot a circle with formula

**x^2 +y^2 +8x + 7 = 0** in Mathematica (on a raspberry pi3 + raspbian).

Without converting the formula to x-a)^2+(y-b)^2=r^2.

I'm looking for something like: Plot[x^2 +y^2 +8x + 7 = 0, ...??.....].

Is this possible?

### Re: Plot a circle.

Posted: **Mon Feb 26, 2018 3:08 pm**

by **jardino**

Try:

- circle.jpg (58.15 KiB) Viewed 10896 times

The first equals sign is important.

Have a look at the current issue of MagPi for tips.

Alan.

### Re: Plot a circle.

Posted: **Mon Feb 26, 2018 4:21 pm**

by **henkoegema**

Thanks very much Alan. For your solution and for your tip

That's what I was looking for.

I'm a total beginner.( not in mathematics, but in Mathematica)

### Re: Plot a circle.

Posted: **Mon Feb 26, 2018 8:16 pm**

by **jardino**

My pleasure.

I'm not a total beginner, but am still dipping my toes in the water.

Alan.

### Re: Plot a circle.

Posted: **Mon Feb 26, 2018 8:22 pm**

by **henkoegema**

jardino wrote: ↑Mon Feb 26, 2018 8:16 pm

My pleasure.

I'm not a total beginner, but am still dipping my toes in the water.

Alan.

I'm trying to do the same.

It's nearly 50 years ago I was a math teacher.

Have forgotten a lot. So I'm refreshing my (old) brains.

### Re: Plot a circle.

Posted: **Mon Feb 26, 2018 8:32 pm**

by **Mortimer**

You have more than one brain! Lucky you!

### Re: Plot a circle.

Posted: **Tue Feb 27, 2018 9:34 am**

by **jardino**

My problem in learning Mathematic is not the maths (I'm fairly competent in maths), but finding a suitable goal to work to.

I bought Schaum's outline on Mathematica, but got bored doing exercise after exercise.

Alan.

### Re: Plot a circle.

Posted: **Tue Feb 27, 2018 10:05 am**

by **henkoegema**

jardino wrote: ↑Tue Feb 27, 2018 9:34 am

My problem in learning Mathematic is not the maths (I'm fairly competent in maths), but finding a suitable goal to work to.

I bought Schaum's outline on Mathematica, but got bored doing exercise after exercise.

Alan.

I didn't know about the book Schaum's outline on Mathematica.

Thanks for mentioning it. It's perfect for me.

### Re: Plot a circle.

Posted: **Tue Feb 27, 2018 11:12 am**

by **jardino**

Second Edition: ISBN-13:978-0-07-160828-2.

(Though Amazon don't believe in ISBN numbers.)

Alan.

### Re: Plot a circle.

Posted: **Sat Mar 03, 2018 1:50 pm**

by **Micha1982**

I am a complete math-noob...but I love mathematica (and internet

)...it offers so many possibilities to play around and create interesting pictures and videos...: