A) Over what interval(s) of t is the parametric curve defined by x=1+t2 y=t-t3 concave downward?
B) Given the parametric equations lnx= t and y= e5t+1.
1) Eliminate the parameter to determine a Cartesian equation for the curve in y= f(x) form.
2) given the parametric equations and any restrictions on the parameter t, identify the bounds for the values of x and y. State the range of values using interval notation.