5. For what value(s) of \( t \) does the curve defined by the parametric equations \( x = \frac{5t}{1 + t^3} \) and \( y = \frac{2t^2}{1 + t^3} \) have a horizontal tangent?
Answer is: option4
Solution:
0 and \( \frac{3}{\sqrt{2}} \) only
