60.4k views
1 vote
Use the basic integration rules to find or evaluate the integral. ∫₁ᵉ ln(9x)/x dx

1 Answer

3 votes

The problem is asking to find the definite integral of ln(9x)/x from 1 to e. To solve this quickly, we can use the formula for the integral of ln(ax) which is x(ln(ax) - 1).

However, as the limits of integration are from 1 to e and there's a 1/x outside of the ln(9x), this problem becomes a straightforward application of the first fundamental theorem of calculus.

Here are the steps for calculating this integral:

Step 1: Identify the integral that needs to be evaluated.
This integral is ∫ from 1 to e ln(9x)/x dx.

Step 2: Rewrite the integral in a more convenient form.
We rewrite the given integral into a more convenient form by factoring out the constant from the natural logarithm as: ∫ from 1 to e ln(9) + ln(x) dx.

Step 3: Break down the integral into simpler parts.
This is accomplished by splitting the integral into two terms so it can be easily solved: ∫ from 1 to e ln(9) dx + ∫ from 1 to e ln(x) dx.

Step 4: Evaluate each integral separately.
The integral of ln(9) with respect to x from 1 to e is e*ln(9) - ln(9) = ln(9)*(e - 1).
The integral of ln(x) with respect to x from 1 to e is e*ln(e) - 1*ln(1) = e - 0 = e.

Step 5: Combine the results.
We now add the values computed in the previous step: ln(9)*(e - 1) + e.

Upon performing the above steps, we determine that the integral ∫ from 1 to e ln(9x)/x dx is equal to 5.11112249896138 - log(9)^2/2.

User Instantsetsuna
by
7.8k points