In which of the following intervals, the function $f(x) = x^2 - 2x + 15$ is decreasing?
Answer & explanation
Correct answer: option 2
The correct answer is Option (1) → $(-1,∞)$
$f(x)=x^2-2x+15$
$\frac{df}{dx}=2x-2$
Function is decreasing when $\frac{df}{dx}<0$
$2x-2<0$
$x<1$
Hence the function is decreasing on $(-\infty,1)$
The correct interval is $(-\infty,1)$.