Answer :
Answer:
- 1) No,
- 2) Yes, x ≈ 5.32
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Part 1
Given sequence:
- t(n) = 5 · 2ⁿ
If t(n) = 200, we can try to find the value of n:
- 5 · 2ⁿ = 200
- 2ⁿ = 40
There is no integer solution, since 32 < 40 < 64 or 2⁵ < 40 < 2⁶, the value of n should be between 5 and 6.
The sequence should include integer numbers, so there is no solution.
Part 2
Given function:
- f(x) = 5 · 2ˣ
Solve for x if f(x) is 200:
- 5 · 2ˣ = 200
- 2ˣ = 40
- log 2ˣ = log 40
- x log 2 = log 40
- x = log 40 / log 2
- x = 5.32 (rounded)
Answer:
1. No
[tex]\textsf{2.} \quad x=\dfrac{\ln 40}{\ln 2} \approx5.32\;(\sf 2\;d.p.)[/tex]
Step-by-step explanation:
Question 1
Given sequence:
[tex]t(n)=5 \cdot 2^n[/tex]
To determine if the sequence has a term with a value of 200, substitute t(n)=200 into the equation and solve for n:
[tex]\implies 5 \cdot 2^n=200[/tex]
[tex]\implies 2^n=40[/tex]
[tex]\implies \ln 2^n=\ln 40[/tex]
[tex]\implies n\ln 2=\ln 40[/tex]
[tex]\implies n=\dfrac{\ln 40}{\ln 2}[/tex]
[tex]\implies n=5.3219280...[/tex]
In a sequence, n is a positive integer. Therefore, it is not possible for the sequence to have a term with the value of 200, as when t(n)=200, n is not a positive integer.
Question 2
Given function:
[tex]f(x)=5 \cdot 2^x[/tex]
To determine if the function has an output of 200, substitute f(x)=200 into the function and solve for x:
[tex]\implies 5 \cdot 2^x=200[/tex]
[tex]\implies 2^x=40[/tex]
[tex]\implies \ln 2^x=\ln 40[/tex]
[tex]\implies x=\dfrac{\ln 40}{\ln 2}[/tex]
[tex]\implies x=5.3219280...[/tex]
Therefore, it is possible for the function to have an output of 200 when:
[tex]x=\dfrac{\ln 40}{\ln 2}[/tex]