For the function below, determine the range of xvalues for which the function is concave up:
1) Assuming k is negative.
2) Assuming k is positive.
Graphing this, I see the curve as concave up between the x values for which the function is undefined.
When k is positive, this does not happen.
When k is negative this happens when x^2 = 1/k, or k=1/x^2. Thus the values of x are between +/ sqrt(1/k), remembering that k itself is negative.

Posted by Charlie
on 20140826 17:19:21 