WOLFRAM|DEMONSTRATIONS PROJECT

Tangent on a Logarithmic Spiral

c

1

a

0.3

θ

-1.0472

leg of triangle

1

The logarithmic spiral

r=c

aθ

e

has the property that the angle (say

α

) between a radius vector to a point on the curve and the tangent at the point is a constant, namely

tan(α)=1/a

.