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If G and L are the greatest and least va...

If G and L are the greatest and least values of the expression`(2x^(2)-3x+2)/(2x^(2)+3x+2), x epsilonR` respectively.
The least value of `G^(100)+L^(100)` is
(a) `2^(100)` (b) `3^(100)` (c) `7^(100)` (d) none of these

A

`2^(100)`

B

`3^(100)`

C

`7^(100)`

D

none of these

Text Solution

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The correct Answer is:
To solve the problem, we need to find the greatest and least values of the expression \[ \frac{2x^2 - 3x + 2}{2x^2 + 3x + 2} \] for \( x \in \mathbb{R} \), and then compute the least value of \( G^{100} + L^{100} \), where \( G \) is the greatest value and \( L \) is the least value of the expression. ### Step 1: Set the expression equal to \( y \) We start by letting \[ y = \frac{2x^2 - 3x + 2}{2x^2 + 3x + 2} \] Cross-multiplying gives us: \[ y(2x^2 + 3x + 2) = 2x^2 - 3x + 2 \] ### Step 2: Rearranging the equation Rearranging this equation leads to: \[ 2yx^2 + 3yx + 2y - 2x^2 + 3x - 2 = 0 \] Combining like terms, we have: \[ (2y - 2)x^2 + (3y + 3)x + (2y - 2) = 0 \] ### Step 3: Using the discriminant For this quadratic equation in \( x \) to have real solutions, the discriminant must be non-negative: \[ D = (3y + 3)^2 - 4(2y - 2)(2y - 2) \geq 0 \] Calculating the discriminant: \[ D = (3y + 3)^2 - 4(2y - 2)^2 \] Expanding this gives: \[ D = 9y^2 + 18y + 9 - 4(4y^2 - 8y + 4) \] \[ = 9y^2 + 18y + 9 - 16y^2 + 32y - 16 \] \[ = -7y^2 + 50y - 7 \geq 0 \] ### Step 4: Finding the roots of the quadratic To find the values of \( y \), we need to solve the quadratic equation: \[ -7y^2 + 50y - 7 = 0 \] Using the quadratic formula \( y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \): \[ y = \frac{-50 \pm \sqrt{50^2 - 4(-7)(-7)}}{2(-7)} \] \[ = \frac{-50 \pm \sqrt{2500 - 196}}{-14} \] \[ = \frac{-50 \pm \sqrt{2304}}{-14} \] \[ = \frac{-50 \pm 48}{-14} \] Calculating the two roots: 1. \( y = \frac{-2}{-14} = \frac{1}{7} \) 2. \( y = \frac{-98}{-14} = 7 \) ### Step 5: Identifying \( G \) and \( L \) From the roots, we identify: - The least value \( L = \frac{1}{7} \) - The greatest value \( G = 7 \) ### Step 6: Calculating \( G^{100} + L^{100} \) Now we need to find \( G^{100} + L^{100} \): \[ G^{100} + L^{100} = 7^{100} + \left(\frac{1}{7}\right)^{100} = 7^{100} + \frac{1}{7^{100}} \] ### Step 7: Finding the least value The term \( \frac{1}{7^{100}} \) is very small compared to \( 7^{100} \), so the least value of \( G^{100} + L^{100} \) is approximately: \[ 7^{100} \] Thus, the least value of \( G^{100} + L^{100} \) is: \[ \boxed{7^{100}} \]

To solve the problem, we need to find the greatest and least values of the expression \[ \frac{2x^2 - 3x + 2}{2x^2 + 3x + 2} \] for \( x \in \mathbb{R} \), and then compute the least value of \( G^{100} + L^{100} \), where \( G \) is the greatest value and \( L \) is the least value of the expression. ...
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