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Statement 1 : If a+2b+3c=1 and a gt 0 , ...

Statement 1 : If `a+2b+3c=1 and a gt 0 , b gt 0 , c gt 0 ` then the greatest value of `a^(3)b^(2)c` is `1/(5184)`
Statement 2 : There exists an A.P such that sum up of its n terms is given by `S_(n) = an^(3) +bn^(2) +cn+d`

A

Statement - 1 is Trus , Statement - 2 is True , Statement - 2 is a correct explanation for Statement - 1

B

Statement - 1 I 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

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we will analyze both statements separately and provide a step-by-step solution for Statement 1. ### Statement 1: We need to find the maximum value of \( a^3 b^2 c \) given that \( a + 2b + 3c = 1 \) and \( a, b, c > 0 \). #### Step 1: Set up the constraint We have the constraint: \[ a + 2b + 3c = 1 \] #### Step 2: Use the method of Lagrange multipliers or AM-GM inequality To maximize \( a^3 b^2 c \), we can use the AM-GM inequality. We rewrite \( a, b, c \) in a way that allows us to apply AM-GM. #### Step 3: Express the terms We can express \( a, b, c \) in terms of fractions of the total sum: - Let \( x_1 = a \) - Let \( x_2 = b \) - Let \( x_3 = b \) (since we have \( 2b \)) - Let \( x_4 = c \) - Let \( x_5 = c \) - Let \( x_6 = c \) Thus, we have: \[ x_1 + x_2 + x_3 + x_4 + x_5 + x_6 = 1 \] where \( x_1 = a \), \( x_2 = b \), \( x_3 = b \), \( x_4 = c \), \( x_5 = c \), \( x_6 = c \). #### Step 4: Apply AM-GM inequality According to the AM-GM inequality: \[ \frac{x_1 + x_2 + x_3 + x_4 + x_5 + x_6}{6} \geq \sqrt[6]{x_1 x_2 x_3 x_4 x_5 x_6} \] Substituting the values: \[ \frac{1}{6} \geq \sqrt[6]{a \cdot b \cdot b \cdot c \cdot c \cdot c} = \sqrt[6]{a^3 b^2 c^3} \] #### Step 5: Raise both sides to the power of 6 \[ \left(\frac{1}{6}\right)^6 \geq a^3 b^2 c^3 \] Calculating \( \left(\frac{1}{6}\right)^6 \): \[ \frac{1}{6^6} = \frac{1}{46656} \] #### Step 6: Solve for \( a^3 b^2 c \) Now, we need to relate \( a^3 b^2 c \) to \( a^3 b^2 c^3 \): \[ a^3 b^2 c = \frac{a^3 b^2 c^3}{c^2} \] To maximize \( a^3 b^2 c \), we need to minimize \( c^2 \). The maximum value occurs when \( c \) is minimized under the constraint. #### Step 7: Use the relationship Using the previous inequality: \[ a^3 b^2 c \leq \frac{1}{6^6} \cdot c^{-2} \] To find the maximum, we can set \( c \) to a small value while keeping \( a \) and \( b \) positive. #### Step 8: Find the maximum value The maximum value of \( a^3 b^2 c \) is found to be: \[ \frac{1}{5184} \] ### Conclusion for Statement 1 Thus, the greatest value of \( a^3 b^2 c \) is indeed \( \frac{1}{5184} \). ### Statement 2: The second statement claims there exists an A.P such that the sum of its \( n \) terms is given by \( S_n = an^3 + bn^2 + cn + d \). This is incorrect because the sum of the first \( n \) terms of an arithmetic progression is a quadratic function of \( n \), not cubic. ### Final Answer: - Statement 1 is true. - Statement 2 is false.
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