I've labelled the image with my questions. Using the Claude Shannon expression we have to find the capacity of this signal.

I've labelled the image with my questions. Using the Claude Shannon expression we have to find the capacity of this signal.

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The logarithm of a number is the exponent to which we have to raise the base to get that number. In this case we have:
$$\log_{10}(S/N)=3$$
so the base is $10$, the number is $S/N$ and the exponent (Thebes's value of the logarithm) is $3$, hence by definition of logarithm we get:
$$10^3=S/N.$$
For the second issue, we want to evaluate $\log_2(1001)$, but we prefer to change the base; this is possible by means the following formula:
$$\log_ab={\log_cb\over\log_ca}$$
so $\log_21001={\log_{10}1001\over\log_{10}2}$, now you can calculate it by your calculator.