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Find the 7th term from the end in the e...

Find the 7th term from the end in the expansion of `(x+(1)/(x))^(11)`

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To find the 7th term from the end in the expansion of \( (x + \frac{1}{x})^{11} \), we can follow these steps: ### Step 1: Identify the general term in the binomial expansion The general term \( T_r \) in the expansion of \( (p + q)^n \) is given by: \[ T_r = \binom{n}{r-1} p^{n - (r-1)} q^{r-1} \] In our case, \( p = x \), \( q = \frac{1}{x} \), and \( n = 11 \). ### Step 2: Determine the term from the end To find the 7th term from the end, we can use the relation: \[ \text{rth term from the end} = (n - r + 2) \text{th term from the beginning} \] Here, \( n = 11 \) and we want the 7th term from the end, so: \[ r = 7 \implies \text{term from the beginning} = 11 - 7 + 2 = 6 \] ### Step 3: Calculate the 6th term from the beginning Using the general term formula: \[ T_6 = \binom{11}{6-1} x^{11 - (6-1)} \left(\frac{1}{x}\right)^{6-1} \] This simplifies to: \[ T_6 = \binom{11}{5} x^{11 - 5} \left(\frac{1}{x}\right)^{5} \] \[ = \binom{11}{5} x^6 \cdot \frac{1}{x^5} = \binom{11}{5} x^{6-5} = \binom{11}{5} x^1 \] ### Step 4: Calculate \( \binom{11}{5} \) Using the formula for combinations: \[ \binom{n}{r} = \frac{n!}{r!(n-r)!} \] We calculate: \[ \binom{11}{5} = \frac{11!}{5! \cdot 6!} = \frac{11 \times 10 \times 9 \times 8 \times 7}{5 \times 4 \times 3 \times 2 \times 1} = 462 \] ### Step 5: Final term calculation Thus, the 6th term is: \[ T_6 = 462 x \] ### Conclusion Therefore, the 7th term from the end in the expansion of \( (x + \frac{1}{x})^{11} \) is: \[ \boxed{462x} \]

To find the 7th term from the end in the expansion of \( (x + \frac{1}{x})^{11} \), we can follow these steps: ### Step 1: Identify the general term in the binomial expansion The general term \( T_r \) in the expansion of \( (p + q)^n \) is given by: \[ T_r = \binom{n}{r-1} p^{n - (r-1)} q^{r-1} \] In our case, \( p = x \), \( q = \frac{1}{x} \), and \( n = 11 \). ...
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NAGEEN PRAKASHAN ENGLISH-BINOMIAL THEOREM-Exercise 8B
  1. Find the 10th term in the binomial expansion of (2x^2+1/x)^(12)dot

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  2. Find the (r+1)th term in the expansion of ((x)/(a)-(a)/(x))^(2n)

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  3. Find the 7th term from the end in the expansion of (x+(1)/(x))^(11)

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  4. Find the 3rd term the end in the expansion of (2-3x)^(8)

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  5. Find the 4th term from the end in the expansion of ((x)/(2)-(4)/(x))^(...

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  6. Find the middle term in the following expansion: (i) (x^(2)-1/x^2)^(...

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  7. In the expansion of (1 + x)^(2n)(n in N), the coefficients of (p +1...

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  8. If the coefficients of the (2r+4)t h ,(r+2)t h term in the expansion o...

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  9. about to only mathematics

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  10. Find a if 17th and 18th terms in the expansion of (2+a)^(50) are eq...

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  11. If the coefficient of 2nd, 3rd and 4th terms in the expansion of (1...

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  12. If n is an odd positive integer, prove that the coefficients of the mi...

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  13. If 3rd, 4th, 5th terms in the expansion of (x+a)^n be 84, 280 and 560,...

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  14. Find a, b and n in the expansion of (a+b)^nif the first three terms ...

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  15. If a. b, c and d are the coefficients of 2nd, 3rd, 4th and 5th terms r...

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  16. The coefficient of three consecutive terms in the expansion of (1+x)^(...

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  17. Find the 4^(t h)term in the expansion of (x-2y)^(12).

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  18. Find the 6th term in the expansion of ((4x)/5-5/(2x))^9dot

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  19. Find the 15th term in the expansion of (2y-(x)/(2))^(18)

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  20. (i) Find the 9th term in the expansion of ((x)/(a)-(2a)/(x^(2)))^(12) ...

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