Tangent Command

Tangent( <Point>, <Conic> ): Creates (all) tangents through the point to the conic section.

Tangent((5, 4), 4x^2 - 5y^2 = 20) yields x - y = 1.

Tangent( <Point>, <Function> ): Creates the tangent to the function at x = x(A).

Tangent((1, 0), x^2) yields y = 2x - 1.

x(A) is the x-coordinate of the given point A.

Tangent( <Point on Curve>, <Curve> ): Creates the tangent to the curve in the given point.

Tangent((0, 1), Curve(cos(t), sin(t), t, 0, π)) yields y = 1.

Tangent( <x-Value>, <Function> ): Creates the tangent to the function at x-Value.

Tangent(1, x^2) yields y = 2x - 1.

Tangent( <Line>, <Conic> ): Creates (all) tangents to the conic section that are parallel to the given line.

Tangent(y = 4, x^2 + y^2 = 4) yields y = 2 and y = -2.

Tangent( <Circle>, <Circle> ): Creates the common tangents to the two Circles (up to 4).

Tangent(x^2 + y^2 = 4, (x - 6)^2 + y^2 = 4) yields y = 2, y = -2, 1.49x + 1.67y = 4.47 and -1.49x + 1.67y = -4.47.

Tangent( <Point>, <Spline> ): Creates the tangent to the spline in the given point.

Let A = (0, 1), B = (4, 4) and C = (0, 4). Tangent(A, Spline({A, B, C})) yields line a: y = 0.59x + 1.

Tangent( <Point>, <Implicit Curve> ): Creates the tangent to the implicit curve in the given point.

Tangent((1,1), x^2+y^2=1)) yields lines x=1 and y=1.