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Let lim ( x to oo) n ^((1)/(2 )(1+(1 )/(...

Let `lim _( x to oo) n ^((1)/(2 )(1+(1 )/(n))). (1 ^(1) . 2 ^(2) . 3 ^(3)....n ^(n ))^((1)/(n ^(2)))=e^((-p)/(q)) `
where p and q are relative prime positive integers. Find the value of `|p+q|.`

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To solve the limit problem given by \[ \lim_{n \to \infty} n^{\frac{1}{2}\left(1 + \frac{1}{n}\right)} \left(1^1 \cdot 2^2 \cdot 3^3 \cdots n^n\right)^{\frac{1}{n^2}} = e^{-\frac{p}{q}}, \] where \( p \) and \( q \) are relatively prime positive integers, we will follow these steps: ### Step 1: Rewrite the limit expression Let \[ L = \lim_{n \to \infty} n^{\frac{1}{2}\left(1 + \frac{1}{n}\right)} \left(1^1 \cdot 2^2 \cdot 3^3 \cdots n^n\right)^{\frac{1}{n^2}}. \] ### Step 2: Take the logarithm of \( L \) Taking the natural logarithm of both sides, we have: \[ \log L = \lim_{n \to \infty} \left( \frac{1}{2}\left(1 + \frac{1}{n}\right) \log n + \frac{1}{n^2} \log(1^1 \cdot 2^2 \cdots n^n) \right). \] ### Step 3: Simplify the logarithm of the product The logarithm of the product can be expressed as: \[ \log(1^1 \cdot 2^2 \cdots n^n) = \sum_{k=1}^{n} k \log k. \] Thus, \[ \log L = \lim_{n \to \infty} \left( \frac{1}{2}\left(1 + \frac{1}{n}\right) \log n + \frac{1}{n^2} \sum_{k=1}^{n} k \log k \right). \] ### Step 4: Analyze the first term As \( n \to \infty \), the first term becomes: \[ \frac{1}{2}\left(1 + \frac{1}{n}\right) \log n \to \frac{1}{2} \log n. \] ### Step 5: Analyze the second term For the second term, we can approximate the sum using integrals: \[ \sum_{k=1}^{n} k \log k \approx \int_1^n x \log x \, dx. \] Calculating this integral: \[ \int x \log x \, dx = \frac{x^2}{2} \log x - \frac{x^2}{4} + C. \] Evaluating from 1 to \( n \): \[ \left[ \frac{n^2}{2} \log n - \frac{n^2}{4} \right] - \left[ \frac{1}{2} \log 1 - \frac{1}{4} \right] = \frac{n^2}{2} \log n - \frac{n^2}{4} + \frac{1}{4}. \] Thus, \[ \sum_{k=1}^{n} k \log k \approx \frac{n^2}{2} \log n - \frac{n^2}{4}. \] ### Step 6: Substitute back into the limit Now substituting back into our expression for \( \log L \): \[ \log L = \lim_{n \to \infty} \left( \frac{1}{2} \log n + \frac{1}{n^2} \left( \frac{n^2}{2} \log n - \frac{n^2}{4} \right) \right). \] This simplifies to: \[ \log L = \lim_{n \to \infty} \left( \frac{1}{2} \log n + \frac{1}{2} \log n - \frac{1}{4} \right) = \lim_{n \to \infty} \log n - \frac{1}{4}. \] ### Step 7: Evaluate the limit As \( n \to \infty \), \( \log n \to \infty \), thus: \[ \log L \to -\frac{1}{4}. \] ### Step 8: Exponentiate to find \( L \) Thus, we have: \[ L = e^{-\frac{1}{4}}. \] ### Step 9: Identify \( p \) and \( q \) From the expression \( e^{-\frac{p}{q}} = e^{-\frac{1}{4}} \), we identify \( p = 1 \) and \( q = 4 \). Since \( p \) and \( q \) are relatively prime, we find: \[ |p + q| = |1 + 4| = 5. \] ### Final Answer The value of \( |p + q| \) is \[ \boxed{5}. \]
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VIKAS GUPTA (BLACK BOOK) ENGLISH-INDEFINITE AND DEFINITE INTEGRATION-EXERCISE (SUBJECTIVE TYPE PROBLEMS)
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  2. If int (dx )/(cos ^(3) x-sin ^(3))=A tan ^(-1) (f (x)) +bln |(sqrt2+f ...

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  3. Find the value of |a| for which the area of triangle included between ...

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  4. Let I = int (0) ^(pi) x ^(6) (pi-x) ^(8)dx, then (pi ^(15))/((""^(15) ...

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  5. If I = int (0) ^(100) (sqrtx)dx, then the value of (9I)/(155) is:

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  6. Let I(n) = int (0)^(pi) (sin (n + (1)/(2))x )/(sin ((x)/(2)))dx where ...

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  7. If M be the maximum value of 72 int (0) ^(y) sqrt(x ^(4) +(y-y^(2))^(2...

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  8. Find the number points where f (theta) = int (-1)^(1) (sin theta dx )/...

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  9. underset(nrarroo)lim[(1)/(sqrtn)+(1)/(sqrt(2n))+(1)/(sqrt(3n))+...+(1)...

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  10. The maximum value of int (-pi//2) ^(2pi//2) sin x. f (x) dx, subject t...

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  11. Given a function g, continous everywhere such that g (1)=5 and int (0)...

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  12. If f (n)= 1/pi int (0) ^(pi//2) (sin ^(2) (n theta) d theta)/(sin ^(2)...

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  13. Let f (2-x) =f (2+xand f (4-x )= f (4+x). Function f (x) satisfies int...

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  14. Let l (n) =int (-1) ^(1) |x|(1+ x+ (x ^(2))/(2 ) +(x ^(3))/(3) + ........

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  15. Let lim ( x to oo) n ^((1)/(2 )(1+(1 )/(n))). (1 ^(1) . 2 ^(2) . 3 ^(3...

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  16. If int (a )^(b) |sin x |dx =8 and int (0)^(a+b) |cos x| dx=9 then the ...

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  17. If f(x),g(x),h(x) and phi(x) are polynomial in x, (int1^x f(x) h(x) dx...

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  18. If int (0)^(2)(3x ^(2) -3x +1) cos (x ^(3) -3x ^(2)+4x -2) dx = a sin ...

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  19. let f (x) = int (0) ^(x) e ^(x-y) f'(y) dy - (x ^(2) -x+1)e ^(x) Fin...

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  20. For a positive integer n, let I (n) =int (-pi)^(pi) ((pi)/(2) -|x|) co...

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