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Consider an AP with a as the first term ...

Consider an AP with a as the first term and d is the common difference such that `S_(n)` denotes the sum to n terms and `a_(n)` denotes the nth term of the AP. Given that for some m,`n inN,(S_(m))/(S_(n))=(m^(2))/(n^(2))(nen)`.
Statement 1 `d=2a` because
Statement 2 `(a_(m))/(a_(n))=(2m+1)/(2n+1)`.

A

Statement 1 is true, Statement 2 is true, Statement 2 is a corrct explanation for Statement 1.

B

Statement 1 is true, Statement 2 is true, Statement 2 is not a correct explanation for Statement 1.

C

Statement 1 is true, Statement 2 is false.

D

Statement 1 is false, Statement 2 is true.

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To solve the problem, we need to analyze the given statements about the arithmetic progression (AP) defined by its first term \( a \) and common difference \( d \). ### Step 1: Understanding the Sum of n Terms of an AP The sum of the first \( n \) terms of an AP is given by the formula: \[ S_n = \frac{n}{2} \left(2a + (n-1)d\right) \] This can be simplified to: \[ S_n = \frac{n}{2} \left(2a + nd - d\right) = \frac{n}{2} \left((n-1)d + 2a\right) \] ### Step 2: Setting Up the Given Ratio We are given that: \[ \frac{S_m}{S_n} = \frac{m^2}{n^2} \] Substituting the formula for \( S_m \) and \( S_n \): \[ \frac{\frac{m}{2} \left(2a + (m-1)d\right)}{\frac{n}{2} \left(2a + (n-1)d\right)} = \frac{m^2}{n^2} \] This simplifies to: \[ \frac{m(2a + (m-1)d)}{n(2a + (n-1)d)} = \frac{m^2}{n^2} \] ### Step 3: Cross Multiplying Cross multiplying gives us: \[ m(2a + (m-1)d) \cdot n^2 = n(2a + (n-1)d) \cdot m^2 \] Expanding both sides: \[ mn^2(2a + (m-1)d) = nm^2(2a + (n-1)d) \] Dividing both sides by \( mn \) (assuming \( m, n \neq 0 \)): \[ n(2a + (m-1)d) = m(2a + (n-1)d) \] ### Step 4: Rearranging the Equation Rearranging gives: \[ 2an - 2am + n(m-1)d = m(n-1)d \] This simplifies to: \[ 2a(n - m) = d(m(n - 1) - n(m - 1)) \] ### Step 5: Analyzing the Statements 1. **Statement 1: \( d = 2a \)** - If we assume \( d = 2a \), substituting this into our equation will help us check if it holds true. - If \( d = 2a \), substituting gives us a consistent equation. 2. **Statement 2: \( \frac{a_m}{a_n} = \frac{2m + 1}{2n + 1} \)** - The nth term of an AP is given by: \[ a_n = a + (n-1)d \] - Thus, we have: \[ a_m = a + (m-1)d \quad \text{and} \quad a_n = a + (n-1)d \] - Substituting \( d = 2a \) into \( a_m \) and \( a_n \) gives: \[ a_m = a + (m-1)(2a) = a + 2a(m-1) = 2am - a \] \[ a_n = a + (n-1)(2a) = a + 2a(n-1) = 2an - a \] - Thus: \[ \frac{a_m}{a_n} = \frac{2am - a}{2an - a} = \frac{2m - 1}{2n - 1} \] - This does not match \( \frac{2m + 1}{2n + 1} \). ### Conclusion - **Statement 1 is true:** \( d = 2a \). - **Statement 2 is false:** \( \frac{a_m}{a_n} \neq \frac{2m + 1}{2n + 1} \).

To solve the problem, we need to analyze the given statements about the arithmetic progression (AP) defined by its first term \( a \) and common difference \( d \). ### Step 1: Understanding the Sum of n Terms of an AP The sum of the first \( n \) terms of an AP is given by the formula: \[ S_n = \frac{n}{2} \left(2a + (n-1)d\right) \] This can be simplified to: ...
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ARIHANT MATHS-SEQUENCES AND SERIES-Exercise (Questions Asked In Previous 13 Years Exam)
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  5. If a1, a2, a3,.....an are in H.P. and a1 a2+a2 a3+a3 a4+.......a(n-1...

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  6. Let Vr denote the sum of the first r terms of an arithmetic progressio...

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