I am not sure how to identify any cusp or vertical tangents. I can find the coordinates of the local extrema using the interval charts, though.

Can somebody help me with these following question:

Q. Determine the ecoordinates of the local extrema. Identify any cusps or vertical tangents.

a) y=-t^(2)e^(3t)

b) y= (x-5)^(1/3)

c) f(x)=(x^(2)-1)^(1/3)