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The sum of (p+q)^(th) and (p-q)^(th) ter...

The sum of `(p+q)^(th) and (p-q)^(th)` terms of an AP equal to

A

A)`(2p)^(th)` term

B

B)`(2q)^(th)` term

C

C)Twice the `p^(th)` term

D

D)Twice the `q^(th)` term

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the sum of the \( (p+q)^{th} \) and \( (p-q)^{th} \) terms of an arithmetic progression (AP). Let's denote the first term of the AP as \( A \) and the common difference as \( D \). ### Step-by-Step Solution: 1. **Identify the Terms**: - The \( n^{th} \) term of an AP can be expressed as: \[ T_n = A + (n-1)D \] - Therefore, the \( (p+q)^{th} \) term is: \[ T_{p+q} = A + (p+q-1)D \] - The \( (p-q)^{th} \) term is: \[ T_{p-q} = A + (p-q-1)D \] 2. **Sum the Terms**: - Now, let's add the two terms: \[ T_{p+q} + T_{p-q} = \left( A + (p+q-1)D \right) + \left( A + (p-q-1)D \right) \] - Simplifying this, we have: \[ = A + (p+q-1)D + A + (p-q-1)D \] - Combining like terms: \[ = 2A + \left( (p+q-1) + (p-q-1) \right)D \] - Simplifying the expression inside the parentheses: \[ = 2A + \left( p + q - 1 + p - q - 1 \right)D \] \[ = 2A + (2p - 2)D \] \[ = 2A + 2(p-1)D \] 3. **Factor Out the 2**: - We can factor out the 2: \[ = 2 \left( A + (p-1)D \right) \] - Recognizing that \( A + (p-1)D \) is the \( p^{th} \) term of the AP: \[ = 2T_p \] ### Conclusion: The sum of the \( (p+q)^{th} \) and \( (p-q)^{th} \) terms of an AP is equal to: \[ 2T_p \] Thus, the correct answer is that the sum equals twice the \( p^{th} \) term of the AP.
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PUNEET DOGRA-SEQUENCE AND SERIES-PREVIOUS YEAR QUESTIONS
  1. What is n^(th) term of the sequence 25,-125,625,-3125, . . .?

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  2. The number 1,5 and 25 can be three terms (not necessarily consecutive)...

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  3. The sum of (p+q)^(th) and (p-q)^(th) terms of an AP equal to

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  4. If a,b,c are in AP or GP or HP. Then (a-b)/(b-c) is equal to:

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  5. If the second term of GP is 2 and the sum of its infinite terms is 8, ...

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  6. Let T, be the rth term of an A.P. for r = 1, 2, 3 … if the some positi...

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  7. The sum of the series 3-1+(1)/(3)-(1)/(9)+ . . . .oo Is equal to: (a...

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  8. If an infinite GP has the first term x and the sum 5, then which one o...

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  9. The third term of a GP is 3. what is the product of the first 5 terms ...

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  10. What is the sum of all two digit numbers which when divided by 3 leave...

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  11. If x, 3/2, z are in AP, x, 3, z are in GP, then which of the following...

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  12. If x=1-y+y^(2)-y^(3)+ up to infinite terms where |y| lt1, then which o...

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  13. If the ratio of AM to GM of two positive numbers a and b is 5:3, then ...

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  14. The value of the product: 6^((1)/(2))xx6^(1/4)xx6^(1/8)xx6^(1/(16))xx....

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  15. If S(n)=nP+(n(n-1)Q)/(2), where S(n) denotes the sum of the first term...

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  16. If y=x+x^(2)+x^(3)+. . . Up to infinite terms, where x lt1, then whic...

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  17. A person is to count 4500 notes. Let a(n) denote the number of notes t...

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  18. If 1.3+2.3^(2)+3.3^(3)+ . . .=n3^(n)=((2n-1)3+b)/(4), then a and b are...

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  19. Let f(n) = [(1)/(2) + (n)/(100)] where [n] denotes the integral part o...

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  20. The fifth term of an AP of n terms, whose sum is n^(2)-2n, is:

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