Which rectangular equation represents the parametric equations x is equal to t raised to the 1 half power and y is equal to 4 t ?

Since x = √t, squaring gives t = x², with x ≥ 0 because a square root is nonnegative. Substitute t = x² into y = 4t to get y = 4x², so the correct choice is B: y = 4x² for x ≥ 0.

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