Find support function of the involutes of circles
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So I have a problem on differential geometry that I am trying to work through.
Determine the support function of the involutes of a circle. Hint: To avoid computations, use the prior exercises.
In the prior exercises I found that if $n(phi)=(cos(phi), sin(phi))$, then $c(phi)=n'(phi)-n(phi)$ parameterizes a circle of radius $sqrt{2}$ centered at the origin. I also found that the evolute is $eta(phi)=h'(phi)n'(phi)-h''(phi)n(phi)$ where $h(phi)$ is the support function.
So I know that the evolute of the involute of a curve $c(t)$ is $c(t)$. And I think that if the support function is a constant, then the curve is a circle but I am not sure how to demonstrate this.
differential-geometry
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add a comment |
$begingroup$
So I have a problem on differential geometry that I am trying to work through.
Determine the support function of the involutes of a circle. Hint: To avoid computations, use the prior exercises.
In the prior exercises I found that if $n(phi)=(cos(phi), sin(phi))$, then $c(phi)=n'(phi)-n(phi)$ parameterizes a circle of radius $sqrt{2}$ centered at the origin. I also found that the evolute is $eta(phi)=h'(phi)n'(phi)-h''(phi)n(phi)$ where $h(phi)$ is the support function.
So I know that the evolute of the involute of a curve $c(t)$ is $c(t)$. And I think that if the support function is a constant, then the curve is a circle but I am not sure how to demonstrate this.
differential-geometry
$endgroup$
add a comment |
$begingroup$
So I have a problem on differential geometry that I am trying to work through.
Determine the support function of the involutes of a circle. Hint: To avoid computations, use the prior exercises.
In the prior exercises I found that if $n(phi)=(cos(phi), sin(phi))$, then $c(phi)=n'(phi)-n(phi)$ parameterizes a circle of radius $sqrt{2}$ centered at the origin. I also found that the evolute is $eta(phi)=h'(phi)n'(phi)-h''(phi)n(phi)$ where $h(phi)$ is the support function.
So I know that the evolute of the involute of a curve $c(t)$ is $c(t)$. And I think that if the support function is a constant, then the curve is a circle but I am not sure how to demonstrate this.
differential-geometry
$endgroup$
So I have a problem on differential geometry that I am trying to work through.
Determine the support function of the involutes of a circle. Hint: To avoid computations, use the prior exercises.
In the prior exercises I found that if $n(phi)=(cos(phi), sin(phi))$, then $c(phi)=n'(phi)-n(phi)$ parameterizes a circle of radius $sqrt{2}$ centered at the origin. I also found that the evolute is $eta(phi)=h'(phi)n'(phi)-h''(phi)n(phi)$ where $h(phi)$ is the support function.
So I know that the evolute of the involute of a curve $c(t)$ is $c(t)$. And I think that if the support function is a constant, then the curve is a circle but I am not sure how to demonstrate this.
differential-geometry
differential-geometry
asked Jan 30 at 20:27
geoplantedgeoplanted
617
617
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