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Question

If $ f'(x) = 3x^2 - \frac{2}{x^2} $; $ f(1) = 0 $ then, $ f (x) $ is

The correct answer is
$ x^3+\frac{2}{x}-3 $

Integrating the Derivative to Find

The problem asks us to find the function $ f(x) $ given its derivative, $ f'(x) = 3x^2 - \frac{2}{x^2} $, and a specific value of the function, $ f(1) = 0 $. This requires us to perform integration and then use the given condition to find the constant of integration.

Step 1: Integrate $f'(x)$

First, we find the indefinite integral of $ f'(x) $ to get the general form of $ f(x) $. We can rewrite $ f'(x) $ as $ f'(x) = 3x^2 - 2x^{-2} $.

The integral is calculated as follows:

$ f(x) = \int f'(x) dx $ $ f(x) = \int (3x^2 - 2x^{-2}) dx $

Using the power rule for integration, which states that $ \int ax^n dx = a \frac{x^{n+1}}{n+1} + C $ (where $ n \neq -1 $):

$ \int 3x^2 dx = 3 \frac{x^{2+1}}{2+1} = 3 \frac{x^3}{3} = x^3 $

And for the second term:

$ \int -2x^{-2} dx = -2 \frac{x^{-2+1}}{-2+1} = -2 \frac{x^{-1}}{-1} = 2x^{-1} = \frac{2}{x} $

Combining these results and adding the constant of integration $ C $:

$ f(x) = x^3 + \frac{2}{x} + C $

Step 2: Use the Condition $f(1) = 0$

We are given that $ f(1) = 0 $. We substitute $ x = 1 $ into the expression for $ f(x) $ we found:

$ f(1) = (1)^3 + \frac{2}{(1)} + C $

Since $ f(1) = 0 $, we set the expression equal to 0:

$ 0 = 1 + 2 + C $ $ 0 = 3 + C $

Solving for $ C $:

$ C = -3 $

Step 3: Determine the Final Function $f(x)$

Now, we substitute the value $ C = -3 $ back into the general form of $ f(x) $:

$ f(x) = x^3 + \frac{2}{x} - 3 $

This is the specific function that satisfies both the derivative $ f'(x) $ and the condition $ f(1) = 0 $.

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Important Questions from Algebra (Notes)

  1. A square matrix having all the elements above the leading diagonal equal to zero is known as:
  2. If $(\frac{7}{11})^{k-5} = (\frac{11}{7})^{k-9}$, find the value of $2^k$.
  3. The sum of the age of A and 5 times the age of B is 36 years. When 3 times the age of A is added to 7 times the age of B, the result is 62 years. The sum of the ages (in years) of A and B is:
  4. 18 bags and 3 pens together cost ₹1,164, whereas 14 bags and 2 pens together cost ₹922. The cost of 9 bags exceeds the cost of 2 pens by:
  5. The cost of 2 pens and 5 notebooks is ₹187. The cost of 8 notebooks exceeds the cost of 4 pens by 40. What is the cost of 8 pens and 7 notebooks?
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