math

Hi

This is a three-part question:

a. the graph y = f(x) in the xy-plane has parametrization x=x, y=f(x), and vector formula r(x) = xi + f(x)j. Use this to show that if f is twice-differentiable, then
((absvalue f''(x))/[1+((f'(x))^2]^3/2

b. use the formula for k in part a to find the curvature of y = ln(cosx) when -pi/2 < x < pi/2.

c. show that the curvature is zero at the point of inflection.

1. 👍 0
2. 👎 0
3. 👁 65
1. You left out something in (a) There is no = sign. It looks like you are trying to compute the curvature of the y = f(x) line, which is defined as the reciprocal of the radius of curvature, or d(phi)/ds, where phi is the slope and x is the arc length.

I suggest you review derivations such as the ones at

or

http://www.everything2.com/index.pl?node_id=1290875

1. 👍 0
2. 👎 0
posted by drwls

Similar Questions

1. math: repost with corrections

p. 942 #5 This is a three-part question: a. the graph y = f(x) in the xy-plane has parametrization x=x, y=f(x), and vector formula r(x) = xi + f(x)j. Use this to show that if f is twice-differentiable, then k(x) = ((absvalue

asked by jaime on December 10, 2007
2. Math

The question is: Fr what value(s) of k will the function f(x)=(kx^2)-4x+k have no zeroes. So for that, the discriminant would be less than 0. 0>D 0>((-4)^2)-4(k)(k) 0>16-(4k^2) 4k^2>16 k^2>4 k>+2/-2 So I know that I'm supposed to

asked by Anonymous on October 14, 2010
3. Math

Me, again... Please help me. Thank you. Assume a plane is flying directly north at 200 mph, but there is a wind blowing west at 23 mph. Part I: Express both the velocity of the plane and the velocity of the wind as vectors, using

asked by Lizzie098 on January 8, 2014
4. Algebra

Consider the two inequalities 2x - 4 < y and y < -2/3x + 2. (b) Graph the region of the plane that satisifies either inequality, or both inequalities. (c) Graph the region of the plane that satisifies either inequality, but NOT

asked by Lilianne on February 4, 2009
5. Physics

I have this very confusing two part question that i am having trouble understanding. For the first question i first created a free body diagram to show the forces acting on both the boxes. However i am unsure of what to do after

asked by joe on February 7, 2017
6. Math Algebra 2

Can someone help me with my assignment? The question is, Give three different quadratic functions that have the same zero/s. Show that they have the same zero/s. Draw their graphs in one Cartesian Plane.(Don't graph it anymore,

asked by Anonymous on April 3, 2016
7. Math 222

This is the second part to my first question A quadratic function Graph the function g(x) = 4 − x2, and state the domain and range. Solution We plot enough points to get the correct shape of the graph. See Fig. 11.10 for the

8. Math 222

This is the second part to my first question A quadratic function Graph the function g(x) = 4 − x2, and state the domain and range. Solution We plot enough points to get the correct shape of the graph. See Fig. 11.10 for the