मराठी

If Rth Term is the Middle Term in the Expansion of ( X 2 − 1 2 X ) 20 Then ( R + 3 ) T H Term Is(A) 20 C 14 ( X 2 14 ) (B) 20 C 12 X 2 2 − 12 (C) − T 20 C 7 X , 2 − 13 (D) None of These - Mathematics

Advertisements
Advertisements

प्रश्न

If rth term is the middle term in the expansion of \[\left( x^2 - \frac{1}{2x} \right)^{20}\]  then \[\left( r + 3 \right)^{th}\]  term is

 

 

पर्याय

  •  \[^{20}{}{C}_{14} \left( \frac{x}{2^{14}} \right)\]

     

  •   \[^{20}{}{C}_{12} x^2 2^{- 12}\]

     

  • \[- ^t{20}{}{C}_7 x, 2^{- 13}\]

     

  •  none of these

     
MCQ
Advertisements

उत्तर

 \[- ^t{20}{}{C}_7 x, 2^{- 13}\]
Here n is even
So, The middle term in the given expansion is
\[\left( \frac{20}{2} + 1 \right)\text{ th = 11th term} \] 
Therefore, (r + 3)th term is the 14th term.
\[T_{14} = ^{20}{}{C}_{13} ( x^2 )^{20 - 13} \left( \frac{- 1}{2x} \right)^{13} \]
`= \left( - 1 \right)^{13} "^20C_{13} \frac{x^{14 - 13}}{2^{13}}`
\[ = - ^{20}{}{C}_7 x 2^{- 13}\]

 

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 18: Binomial Theorem - Exercise 18.4 [पृष्ठ ४८]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 11
पाठ 18 Binomial Theorem
Exercise 18.4 | Q 30 | पृष्ठ ४८

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

Find the coefficient of a5b7 in (a – 2b)12


Write the general term in the expansion of (x2 – y)6


Find the middle terms in the expansions of  `(3 - x^3/6)^7`


In the expansion of (1 + a)m + n, prove that coefficients of am and an are equal.


Find the middle term in the expansion of: 

(i)  \[\left( \frac{2}{3}x - \frac{3}{2x} \right)^{20}\]

 


Find the middle terms(s) in the expansion of: 

(i) \[\left( x - \frac{1}{x} \right)^{10}\]

 


Find the middle terms(s) in the expansion of:

(v) \[\left( x - \frac{1}{x} \right)^{2n + 1}\]

 


Find the middle terms(s) in the expansion of:

(x)  \[\left( \frac{x}{a} - \frac{a}{x} \right)^{10}\]

 


Find the term independent of x in the expansion of the expression: 

(i) \[\left( \frac{3}{2} x^2 - \frac{1}{3x} \right)^9\]

 


Find the term independent of x in the expansion of the expression: 

(iv) \[\left( 3x - \frac{2}{x^2} \right)^{15}\]

 


The coefficients of 5th, 6th and 7th terms in the expansion of (1 + x)n are in A.P., find n.

 

If in the expansion of (1 + x)n, the coefficients of pth and qth terms are equal, prove that p + q = n + 2, where  \[p \neq q\]

 


Find the coefficient of a4 in the product (1 + 2a)4 (2 − a)5 using binomial theorem.

 

Find the sum of the coefficients of two middle terms in the binomial expansion of  \[\left( 1 + x \right)^{2n - 1}\]

 

Write the total number of terms in the expansion of  \[\left( x + a \right)^{100} + \left( x - a \right)^{100}\] .

 

If in the expansion of (a + b)n and (a + b)n + 3, the ratio of the coefficients of second and third terms, and third and fourth terms respectively are equal, then n is


The number of irrational terms in the expansion of \[\left( 4^{1/5} + 7^{1/10} \right)^{45}\]  is

 

In the expansion of \[\left( x^2 - \frac{1}{3x} \right)^9\] , the term without x is equal to

 

The middle term in the expansion of \[\left( \frac{2 x^2}{3} + \frac{3}{2 x^2} \right)^{10}\] is 

 

In the expansion of \[\left( x - \frac{1}{3 x^2} \right)^9\]  , the term independent of x is

 

If in the expansion of (1 + y)n, the coefficients of 5th, 6th and 7th terms are in A.P., then nis equal to


If the sum of odd numbered terms and the sum of even numbered terms in the expansion of  \[\left( x + a \right)^n\]  are A and B respectively, then the value of \[\left( x^2 - a^2 \right)^n\] is 

 

Find the middle term in the expansion of `(2ax - b/x^2)^12`.


Find numerically the greatest term in the expansion of (2 + 3x)9, where x = `3/2`.


Find the middle term (terms) in the expansion of `(x/a - a/x)^10`


Show that the middle term in the expansion of `(x - 1/x)^(2x)` is `(1 xx 3 xx 5 xx ... (2n - 1))/(n!) xx (-2)^n`


If xp occurs in the expansion of `(x^2 + 1/x)^(2n)`, prove that its coefficient is `(2n!)/(((4n - p)/3)!((2n + p)/3)!)`


Middle term in the expansion of (a3 + ba)28 is ______.


The position of the term independent of x in the expansion of `(sqrt(x/3) + 3/(2x^2))^10` is ______.


The number of terms in the expansion of [(2x + y3)4]7 is 8.


The last two digits of the numbers 3400 are 01.


If the coefficient of x10 in the binomial expansion of `(sqrt(x)/5^(1/4) + sqrt(5)/x^(1/3))^60` is 5kl, where l, k ∈ N and l is coprime to 5, then k is equal to ______.


Let the coefficients of the middle terms in the expansion of `(1/sqrt(6) + βx)^4, (1 - 3βx)^2` and `(1 - β/2x)^6, β > 0`, common difference of this A.P., then `50 - (2d)/β^2` is equal to ______.


The term independent of x in the expansion of `[(x + 1)/(x^(2/3) - x^(1/3) + 1) - (x - 1)/(x - x^(1/2))]^10`, x ≠ 1 is equal to ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×