The function f(t) = 4t2 − 8t + 6 shows the height from the ground f(t), in meters, of a roller coaster car at different times t. Write f(t) in the vertex form a(x − h)2 + k, where a, h, and k are integers, and interpret the vertex of f(t).


f(t) = 4(t − 1)2 + 3; the minimum height of the roller coaster is 3 meters from the ground

f(t) = 4(t − 1)2 + 3; the minimum height of the roller coaster is 1 meter from the ground

f(t) = 4(t − 1)2 + 2; the minimum height of the roller coaster is 2 meters from the ground

f(t) = 4(t − 1)2 + 2; the minimum height of the roller coaster is 1 meter from the ground

Verified Answer :

Answer:

The correct option is 3.

Step-by-step explanation:

The vertex form of a parabola is

\(f(x)=a(x-h)^2+k\)            .... (1)

where a, h, and k are integers, and interpret the vertex of f(t). (h,k) is the vertex of the parabola.

The given function is

\(f(x)=4t^2-8t+6\)

It can be written as

\(f(x)=4(t^2-2t)+6\)

If an expression is defined as \(x^2+bx\), then we need to add \((\frac{b}{2})^2\) to make it perfect square.

In the expression \(t^2-2t\) the value of b is -2. So, we nned to add and subtract \((\frac{-2}{2})^2\) in the parenthesis.

\(f(x)=4(t^2-2t+1^2-1^2)+6\)

\(f(x)=4(t^2-2t+1)+4(-1)+6\)

\(f(x)=4(t-1)^2-4+6\)

\(f(x)=4(t-1)^2+2\)                .... (2)

The vertex form of the parabola is \(f(x)=4(t-1)^2+2\).

From (1) and (2), we get h=1 and k=2. It means the vertex of the parabola is (1,2). Vertex of upward parabola is point of minima. So the  minimum height of the roller coaster is 2 meters from the ground.

Therefore the correct option is 3.