The function f(x)=−(x−1)2+2 is a quadratic function in vertex form f(x)=a(x−h)2+k.
From the given function:
- Vertex: (h,k)=(1,2)
- Coefficient: a=−1<0
Since a<0, the parabola opens downward.
For a downward-opening parabola with vertex at x=1:
- The function increases on (−∞,1]
- The function decreases on [1,∞)
Statement (A) is TRUE.
To find critical points, take the derivative:
f′(x)=−2(x−1)
Setting f′(x)=0:
−2(x−1)=0
x=1
A critical point exists at x=1.
Statement (B) is FALSE.
Since the parabola opens downward, the vertex represents the maximum point.
At x=1:
f(1)=−(1−1)2+2
f(1)=2
The function has a maximum value of 2 at x=1.
Statement (C) is TRUE.
Since the parabola opens downward, the vertex represents a maximum, not a minimum.
As x→±∞, f(x)→−∞, so no minimum value exists.
Statement (D) is FALSE.
The correct statements are (A) and (C) only.