Consider the parametric curve given by [math]


(a) Find [math] and [math] in terms of [math].

[math] =

[math] =


(b) Using "less than" and "greater than" notation, list the [math]-interval where the curve is concave upward.

Use upper-case "INF" for positive infinity and upper-case "NINF" for negative infinity. If the curve is never concave upward, type an upper-case "N" in the answer field.

[math]-interval: [math]