Question

Which function is the result of vertically stretching ƒ(x) = x2 by a factor of 2 and translating it 4 units upward?

Question 20 options:

A)

y = –4x2 + 2

B)

y = 4x2 + 2

C)

y = 2x2 + 4

D)

y = 2x2 – 4

Answer 1

C

Explanation:

y= 2x^2 + 4

Answer 2

The correct answer is the letter C.

Explanation:

In order to stretch a function we need to multiply it by the factor we want to stretch, if we want to shrink the function we will have to divide it by the factor. On the other hand in order to translate it we need to sum the factor we want the function to shift. In this case we want to stretch the function by 2, therefore the new function must be 2*f(x), but we also want it to shift by 4 units so it has to be 2*f(x) + 4. Applying the given expression:

`g(x) = 2*f(x) + 4\\g(x) = 2*x^2 + 4`

The correct answer is the letter C.