Answer :

To solve this problem, we need to follow these steps:

1. Define the function [tex]\( f(x) \)[/tex]:
[tex]\[ f(x) = x^2 + 1 \][/tex]

2. Calculate [tex]\( f(4) \)[/tex]:
Substitute [tex]\( x = 4 \)[/tex] into the function [tex]\( f(x) \)[/tex]:
[tex]\[ f(4) = 4^2 + 1 \][/tex]
Compute the value inside the function:
[tex]\[ 4^2 = 16 \][/tex]
Then add 1:
[tex]\[ f(4) = 16 + 1 = 17 \][/tex]

3. Calculate [tex]\( 2 \cdot f(4) \)[/tex]:
Now that we have [tex]\( f(4) = 17 \)[/tex], we need to find twice this value:
[tex]\[ 2 \cdot f(4) = 2 \cdot 17 \][/tex]
Finally, compute the product:
[tex]\[ 2 \cdot 17 = 34 \][/tex]

So, the value of [tex]\( 2 \cdot f(4) \)[/tex] is [tex]\( \boxed{34} \)[/tex].