Question

Given the function f(x) = 4(x + 1)^2 – 3, indicate the shifts that will affect the location of the vertex, and explain what effect they will have. Use complete sentences.
-f(x–2)
-f(x) – 2
-f(2x)
-2⋅f(x)

Answer 1

He first two are relatively easy. f(x-2) shifts it sideways (2 to the right in this case) f(x) -2 shifts it straight down (by 2)
f(2x) means replace x with 2x in the original 4(2x + 1)^2 − 3 if you factor out the 2 from the square root you get 4*sqr(2) ( x + ½)^2 - 3 which is now in the form a ( x -h)^2 + k the vertex is now at (-½, -3) (it used to be at (-1,-3) the "a" has gotten bigger, which makes the parabola "skinnier" (it goes up faster)
2•f(x) becomes 2*( 4(x + 1)2 − 3 ) = 8 (x+1)^2 -6 where is the vertex now? is this parabola fatter or skinnier than the original f(x) ?