which best describes the graph of the cubic function (f(x)=x^{3}+x^{2}+x + 1)?\nas (x) increases, (y)…

which best describes the graph of the cubic function (f(x)=x^{3}+x^{2}+x + 1)?\nas (x) increases, (y) increases along the entire graph.\nas (x) increases, (y) increases, decreases, and then increases again.\nas (x) increases, (y) decreases, increases, and then decreases again.\nas (x) increases, (y) decreases along the entire graph.

which best describes the graph of the cubic function (f(x)=x^{3}+x^{2}+x + 1)?\nas (x) increases, (y) increases along the entire graph.\nas (x) increases, (y) increases, decreases, and then increases again.\nas (x) increases, (y) decreases, increases, and then decreases again.\nas (x) increases, (y) decreases along the entire graph.

Answer

Explanation:

Step1: Find the derivative

Differentiate $f(x)=x^{3}+x^{2}+x + 1$ using the power - rule. The derivative $f^\prime(x)=3x^{2}+2x + 1$.

Step2: Analyze the discriminant of the quadratic

For a quadratic function $ax^{2}+bx + c$ (here $a = 3$, $b = 2$, $c = 1$), the discriminant $\Delta=b^{2}-4ac$. Calculate $\Delta=(2)^{2}-4\times3\times1=4 - 12=-8<0$. And $a = 3>0$, so $f^\prime(x)>0$ for all real $x$.

Step3: Determine the behavior of the function

Since $f^\prime(x)>0$ for all real $x$, the function $y = f(x)$ is increasing for all real values of $x$. That is, as $x$ increases, $y$ increases along the entire graph.

Answer:

As $x$ increases, $y$ increases along the entire graph.