### 4.2.4. Conic Section

A conic section is entered as a quadratic equation in x and y. Prior defined variables (e.g. numbers, points, vectors) can be used. The conic section’s name can be entered at the beginning of the input followed by a colon.

Examples:

· Ellipse ell: ell: 9 x^2 + 16 y^2 = 144

· Hyperbola hyp: hyp: 9 x^2 – 16 y^2 = 144

· Parabola par: par: y^2 = 4 x

· Circle k1: k1: x^2 + y^2 = 25

· Circle k2: k2: (x–5)^2 + (y+2)^2 = 25

Note: If you define two parameters a = 4 and b = 3 in advance, you can enter an ellipse as ell: b^2 x^2 + a^2 y^2 = a^2 b^2.

Related Topics

4.2. Direct Input

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