Hi, I need to find the curvature k of y=sqrt(R^2 - x^2) I know k = |f''| / (1 + f' ^2) ^1.5 But I think I have gone somewhere with my differentiation as I didn't end up with k = 1/R which is the answer :/ Thanks in advance for the help.
Follow Math Help Forum on Facebook and Google+
Originally Posted by PStudent175 Hi, I need to find the curvature k of y=sqrt(R^2 - x^2) I know k = |f''| / (1 + f' ^2) ^1.5 But I think I have gone somewhere with my differentiation as I didn't end up with k = 1/R which is the answer :/ Thanks in advance for the help. clean up the algebra ...
Sorry how did you get y' = -x/y ? I got y' = f' = -x(R^2 - x^2)^-0.5 from the chain rule
implicit derivative ... ... note that is a constant
Ok great thanks, could you also show how you got y'' = -R^2 / y^3 ?
quotient rule ... multiply numerator and denominator by to clear the complex fraction ...
View Tag Cloud