हिंदी

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

 

 

विकल्प

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

     

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

     

  • \[- ^t{20}{}{C}_7 x, 2^{- 13}\]

     

  •  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
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 18: Binomial Theorem - Exercise 18.4 [पृष्ठ ४८]

APPEARS IN

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

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

Find the coefficient of x5 in (x + 3)8


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


Find the 13th term in the expansion of `(9x - 1/(3sqrtx))^18 , x != 0`


Find the middle terms in the expansions of `(x/3 + 9y)^10`


Find the middle term in the expansion of: 

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

 


Find the middle terms in the expansion of: 

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

 


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:

(ii)  \[\left( 1 - 2x + x^2 \right)^n\]


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

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

 


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

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

 


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

(ix) \[\left( \sqrt[3]{x} + \frac{1}{2 \sqrt[3]{x}} \right)^{18} , x > 0\]

 


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

 

If the coefficients of 2nd, 3rd and 4th terms in the expansion of (1 + x)n are in A.P., then find the value of n.


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

 

If the coefficients of three consecutive terms in the expansion of (1 + x)n be 76, 95 and 76, find n.


If the 2nd, 3rd and 4th terms in the expansion of (x + a)n are 240, 720 and 1080 respectively, find xan.


Write the coefficient of the middle term in the expansion of \[\left( 1 + x \right)^{2n}\] . 

 

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

 

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

 

If an the expansion of \[\left( 1 + x \right)^{15}\]   , the coefficients of \[\left( 2r + 3 \right)^{th}\text{  and  } \left( r - 1 \right)^{th}\]  terms are equal, then the value of r is

 

If in the expansion of \[\left( x^4 - \frac{1}{x^3} \right)^{15}\] ,  \[x^{- 17}\]  occurs in rth term, then

 

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 

 

The total number of terms in the expansion of \[\left( x + a \right)^{100} + \left( x - a \right)^{100}\]  after simplification is

 

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

 

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


Find the term independent of x in the expansion of `(3x - 2/x^2)^15`


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


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


The number of rational terms in the binomial expansion of `(4^(1/4) + 5^(1/6))^120` is ______.


If the 4th term in the expansion of `(ax + 1/x)^n` is `5/2` then the values of a and n respectively are ______.


The middle term in the expansion of (1 – 3x + 3x2 – x3)6 is ______.


Let for the 9th term in the binomial expansion of (3 + 6x)n, in the increasing powers of 6x, to be the greatest for x = `3/2`, the least value of n is n0. If k is the ratio of the coefficient of x6 to the coefficient of x3, then k + n0 is equal to ______.


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 ______.


The sum of the real values of x for which the middle term in the binomial expansion of `(x^3/3 + 3/x)^8` equals 5670 is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×