Chapter 2: Space Curves
Section 2.4: Curvature
Example 2.4.2
Show that the circle everywhere has constant curvature, that is, show .
Solution
Mathematical Solution
Implicitly differentiate the equation of the circle to obtain :
Obtain and simplify the denominator of :
The final simplification hinges on the positivity of . Note also that the square root of is , which matters because can be both positive and negative along the circle.
Implicitly differentiate to obtain , the numerator of :
Finally, obtain .
Maple Solution - Interactive
Initialize
Tools≻Load Package: Student Precalculus
Loading Student:-Precalculus
Obtain
Control-drag the equation of the circle and press the Enter key.
Context Panel: Differentiate≻Implicitly In the dialog that appears (see Figure 2.4.2(a)), set as the dependent variable and as the independent variable. Write in the "Differentiate with respect to" box.
Figure 2.4.2(a)
Reference the equation of the circle by its equation label and press the Enter key.
Context Panel: Differentiate≻Implicitly Write in the "Differentiate with respect to" box. (See Figure 2.4.2(a).)
Form and simplify
Using equation labels, write the expression for , then press the Enter key.
Context Panel: Simplify≻Assuming Real
Context Panel: Student Precalculus≻Complete the Square≻Designated Quantities≻
Context Panel: Simplify≻With Side Relations≻
Context Panel: Simplify≻Assuming Positive
Maple Solution - Coded
Define the circle.
Apply the implicitdiff and simplify commands.
Apply the CompleteSquare command from the Student Precalculus package.
Apply the simplify command with as a side relation.
Apply the simplify command.
<< Previous Example Section 2.4 Next Example >>
© Maplesoft, a division of Waterloo Maple Inc., 2025. All rights reserved. This product is protected by copyright and distributed under licenses restricting its use, copying, distribution, and decompilation.
For more information on Maplesoft products and services, visit www.maplesoft.com
Download Help Document