Question

How do you evaluate the function with the given values of x: $f\left( x \right)=4x$ when $x=2,x=1/2$ .

Answer 1

Hint: To evaluate the function $f\left( x \right)=4x$ when $x=2$ , we have to substitute the value for x, that is, 2 in the given function and simplify. To find the value of the given function when $x=1/2$ , we have to substitute this value of x in the given function and simplify.

Complete step by step solution:
We have to evaluate the function $f\left( x \right)=4x$ when $x=2,x=1/2$ . Let us first find the value of the function when $x=2$ . We have to substitute the value of x as 2 in the given function.
$\Rightarrow f\left( x \right)=4\times 2=8$
Now, we have to find the value of the function when $x=\dfrac{1}{2}$ . Similar to the above step, we will substitute the value of x as $\dfrac{1}{2}$ in the given function.
$\Rightarrow f\left( x \right)=4\times \dfrac{1}{2}=2$

Hence, the value of the function when $x=2$ and is $x=\dfrac{1}{2}$ are 8 and 2 respectively.

Note: We can draw a graph with the values found to know the nature of the function. We found that when $x=2$ , the value of the function is 8. Let us denote the value of the function as y. Thus we can write these as a point that can be plotted in the Cartesian plane. We will represent it as $\left( 2,8 \right)$ . Let us plot this point in the graph. Similarly, we obtained the value of the function, $y=2$ when $x=\dfrac{1}{2}$ . We can denote these as $\left( \dfrac{1}{2},2 \right)$ . We will plot this point in the graph. Now, we have to join these points. The graph obtained is shown below.

We can also plot more points to get the nature of the graph clearly. We can also take negative values for x.