Which function will have the greatest value when [tex]\( x \ \textgreater \ 1 \)[/tex]?

1. [tex]\( g(x) = 2(5)^x \)[/tex]
2. [tex]\( f(x) = 2x + 5 \)[/tex]
3. [tex]\( h(x) = 2x^2 + 5 \)[/tex]
4. [tex]\( k(x) = 2x^3 + 5 \)[/tex]



Answer :

To address which function has the greatest value when [tex]\( x > 1 \)[/tex], let's examine and compare the values of the given functions at [tex]\( x = 1.1 \)[/tex]:

1. Function [tex]\( g(x) = 2 \cdot 5^x \)[/tex]

First, we evaluate [tex]\( g(x) \)[/tex] at [tex]\( x = 1.1 \)[/tex]:
[tex]\[ g(1.1) = 2 \cdot 5^{1.1} \][/tex]
Plugging in the value, we find:
[tex]\[ g(1.1) \approx 11.746 \][/tex]

2. Function [tex]\( f(x) = 2x + 5 \)[/tex]

Next, we evaluate [tex]\( f(x) \)[/tex] at [tex]\( x = 1.1 \)[/tex]:
[tex]\[ f(1.1) = 2 \cdot 1.1 + 5 \][/tex]
Simplifying, we get:
[tex]\[ f(1.1) = 2.2 + 5 = 7.2 \][/tex]

3. Function [tex]\( h(x) = 2x^2 + 5 \)[/tex]

Then, we evaluate [tex]\( h(x) \)[/tex] at [tex]\( x = 1.1 \)[/tex]:
[tex]\[ h(1.1) = 2 \cdot (1.1)^2 + 5 \][/tex]
Calculating further,
[tex]\[ h(1.1) = 2 \cdot 1.21 + 5 = 2.42 + 5 = 7.42 \][/tex]

4. Function [tex]\( k(x) = 2x^3 + 5 \)[/tex]

Finally, we evaluate [tex]\( k(x) \)[/tex] at [tex]\( x = 1.1 \)[/tex]:
[tex]\[ k(1.1) = 2 \cdot (1.1)^3 + 5 \][/tex]
Calculating further,
[tex]\[ k(1.1) = 2 \cdot 1.331 + 5 \approx 2.662 + 5 = 7.662 \][/tex]

Now, let's compare all these values:
- [tex]\( g(1.1) \approx 11.746 \)[/tex]
- [tex]\( f(1.1) = 7.2 \)[/tex]
- [tex]\( h(1.1) = 7.42 \)[/tex]
- [tex]\( k(1.1) \approx 7.662 \)[/tex]

The highest value among these is [tex]\( g(1.1) \approx 11.746 \)[/tex].

Hence, the function [tex]\( g(x) = 2 \cdot 5^x \)[/tex] has the greatest value when [tex]\( x > 1 \)[/tex].

Therefore, the correct answer is:
[tex]\[ \boxed{1} \][/tex]

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