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In in the expansion of (1+px)^(q), q bel...

In in the expansion of `(1+px)^(q)`, `q` belongs to `N`, the coefficients of `x` and `x^(2)` are `12` and `60` respectively then `p` and `q` are

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To solve the problem, we need to find the values of \( p \) and \( q \) given the coefficients of \( x \) and \( x^2 \) in the expansion of \( (1 + px)^q \). ### Step-by-Step Solution: 1. **Identify the General Term**: The general term in the expansion of \( (1 + px)^q \) is given by: \[ T_{r+1} = \binom{q}{r} (1)^{q-r} (px)^r = \binom{q}{r} p^r x^r \] 2. **Find the Coefficient of \( x \)**: The coefficient of \( x \) corresponds to \( r = 1 \): \[ \text{Coefficient of } x = T_2 = \binom{q}{1} p^1 = qp \] Given that this coefficient is 12, we have: \[ qp = 12 \quad \text{(1)} \] 3. **Find the Coefficient of \( x^2 \)**: The coefficient of \( x^2 \) corresponds to \( r = 2 \): \[ \text{Coefficient of } x^2 = T_3 = \binom{q}{2} p^2 = \frac{q(q-1)}{2} p^2 \] Given that this coefficient is 60, we have: \[ \frac{q(q-1)}{2} p^2 = 60 \quad \Rightarrow \quad q(q-1)p^2 = 120 \quad \text{(2)} \] 4. **Substituting \( qp \) into Equation (2)**: From equation (1), we can express \( p \) in terms of \( q \): \[ p = \frac{12}{q} \] Substitute \( p \) into equation (2): \[ q(q-1) \left(\frac{12}{q}\right)^2 = 120 \] Simplifying this gives: \[ q(q-1) \frac{144}{q^2} = 120 \] \[ 144(q-1) = 120q \] \[ 144q - 144 = 120q \] \[ 24q = 144 \quad \Rightarrow \quad q = 6 \] 5. **Finding \( p \)**: Substitute \( q = 6 \) back into equation (1): \[ 6p = 12 \quad \Rightarrow \quad p = 2 \] ### Final Answer: Thus, the values of \( p \) and \( q \) are: \[ p = 2, \quad q = 6 \]
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AAKASH INSTITUTE-BINOMIAL THEOREM-Assignment (section-A)
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  3. In in the expansion of (1+px)^(q), q belongs to N, the coefficients of...

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  4. The expansion of (x^(alpha)+1/x^(beta))^(n) has constant term, if

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  12. The middle term in the expansioin of (1+x)^(2n) is

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  13. Cofficient of x^(12) in the expansion of (1+x^(2))^50(x+1/x)^(-10)

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  14. The number of terms in expansion of (x^(2)+18x+81)^(15) is

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  15. The term independent of x in the expanion of (root(6)(x)-(2)/(root(3)(...

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  16. The middle terms in the expansion of (1+x)^(2n+1) is (are)

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