Question:medium

If \[ \int \frac{\sin^3x+\cos^3x}{\sin^2x\cos^2x}\,dx = A\sec x+B\cosec x+c, \] then \((A,B)\) are

Show Hint

Try to convert integrands into known derivative forms like \(\sec x\tan x\) and \(\cosec x\cot x\).
  • \((1,1)\)
  • \((-1,-1)\)
  • \((1,-1)\)
  • \((-1,1)\)
Show Solution

The Correct Option is C

Solution and Explanation

Step 1: Understanding the Question:
This is an integration problem where the result is given in terms of unknown coefficients \( A \) and \( B \).
By performing the integration ourselves, we can compare our result with the provided form to find the values of the constants.
Step 2: Key Formula or Approach:
1. Split the fraction into two parts.
2. Standard integral rules for trigonometric functions.
Step 3: Detailed Explanation:

Split the integrand:
\[ \int \left(\frac{\sin^3 x}{\sin^2 x \cos^2 x} + \frac{\cos^3 x}{\sin^2 x \cos^2 x}\right) dx \]

Simplify each term by canceling common factors:
\[ \int \left(\frac{\sin x}{\cos^2 x} + \frac{\cos x}{\sin^2 x}\right) dx \]

Rewrite as products of reciprocal functions:
\[ \int \left(\frac{\sin x}{\cos x} \cdot \frac{1}{\cos x} + \frac{\cos x}{\sin x} \cdot \frac{1}{\sin x}\right) dx \]
\[ \int (\tan x \sec x + \cot x \text{cosec } x) dx \]

Use standard integration formulas:
\( \int \sec x \tan x dx = \sec x \)
\( \int \text{cosec } x \cot x dx = -\text{cosec } x \)

The total integral result is:
\[ \sec x - \text{cosec } x + c \]

Compare this with the given form \( A \sec x + B \text{cosec } x + c \):
Comparing coefficients: \( A = 1 \) and \( B = -1 \).
The pair \( (A, B) \) is \( (1, -1) \).

Step 4: Final Answer:
The values of the constants are \( A = 1 \) and \( B = -1 \).
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