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I am new to exponents and logarithms, and have been stuck with this for a quite long time.

The problem is:

$$\frac{122312}{100000}=(1+t)^5$$

or

$$\log_{1+t}\frac{122312}{100000}=5$$

I have no idea, how to solve this. Hints or tips would be very very welcomed.

Thank You (a lot) in advance!(also apologies for my poor english)

Brian M. Scott
  • 616,228

4 Answers4

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Why are you taking the logarithm? I think you should compute the fifth root of $\frac{122312}{100000}$ and then subtract $1$ from it to get $t$.
You can use the log table to compute the fifth root of $\frac{122312}{100000}$. (Assuming you know how to use it) Let $$n={\left(\frac{122312}{100000}\right)}^{\frac{1}{5}}$$ then take log on both sides to get $$\log_{10}(n)={\frac{1}{5}}\log_{10}(1.22312)$$ First compute $\log_{10}(n)$ and then using the antilog tables, compute $n$. Then, since $t+1=n$, $t=n-1$

Adi Dani
  • 16,949
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The first equation says that

$$1+t=\sqrt[5]{\frac{122312}{100000}}=\sqrt[5]{1.22312}=1.22312^{1/5}\;;$$

if you’re required only to get a good numerical approximation to $t$, just use any convenient calculator to get

$$t=1.22312^{1/5}-1\approx0.0411033$$

(or however precise an approximation is wanted).

Any exact expression for $t$ is going to be fairly ugly, and without more context it’s not clear even what sort of expression would be wanted.

Brian M. Scott
  • 616,228
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$$\frac{122312}{100000}=(1+t)^5$$ $$1.22312=(1+t)^5$$ $$1+t=\sqrt[5]{1,22312}$$ $$t=\sqrt[5]{1,22312}-1$$

Adi Dani
  • 16,949
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If you really want to go through logarithms, you can do as follows: $$\frac{122312}{100000}=(1+t)^5$$ $$\log_{1+t}\left(\frac{122312}{100000}\right) = 5$$ $$\frac{\ln\left(\frac{122312}{100000}\right)}{\ln(1+t)} = 5$$ $$\ln(t+1) = \frac{\ln\left(\frac{122312}{100000}\right)}{5}$$ $$t = e^\frac{\ln\left(\frac{122312}{100000}\right)}{5} - 1$$ $$t = \left(\frac{122312}{100000}\right)^\frac{1}{5} - 1$$ which is exactly the solution you get by usual means.