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Let f(x)=ax^(2)+bx+c, g(x)=ax^(2)+qx+r, ...

Let `f(x)=ax^(2)+bx+c`, `g(x)=ax^(2)+qx+r`, where `a`, `b`, `c`,`q`, `r in R` and `a lt 0`. If `alpha`, `beta` are the roots of `f(x)=0` and `alpha+delta`, `beta+delta` are the roots of `g(x)=0`, then

A

`f_(max) gt g_(max)`

B

`f_(max) lt g_(max)`

C

`f_(max) = g_(max)`

D

cant say anything about relation between `f_(max)` and `g_(max)`

Text Solution

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The correct Answer is:
To solve the problem, we will analyze the functions \( f(x) \) and \( g(x) \) and their maximum values. ### Step 1: Identify the maximum values of \( f(x) \) and \( g(x) \) Given: - \( f(x) = ax^2 + bx + c \) - \( g(x) = ax^2 + qx + r \) Since \( a < 0 \), both functions are concave down, meaning they have maximum values. The maximum value of a quadratic function \( f(x) = ax^2 + bx + c \) occurs at \( x = -\frac{b}{2a} \). The maximum value can be calculated as: \[ f_{\text{max}} = f\left(-\frac{b}{2a}\right) = a\left(-\frac{b}{2a}\right)^2 + b\left(-\frac{b}{2a}\right) + c \] Calculating \( f_{\text{max}} \): \[ f_{\text{max}} = a\left(\frac{b^2}{4a^2}\right) - \frac{b^2}{2a} + c = \frac{b^2}{4a} - \frac{2b^2}{4a} + c = \frac{-b^2}{4a} + c \] ### Step 2: Calculate the maximum value of \( g(x) \) Similarly, for \( g(x) \): \[ g_{\text{max}} = g\left(-\frac{q}{2a}\right) = a\left(-\frac{q}{2a}\right)^2 + q\left(-\frac{q}{2a}\right) + r \] Calculating \( g_{\text{max}} \): \[ g_{\text{max}} = a\left(\frac{q^2}{4a^2}\right) - \frac{q^2}{2a} + r = \frac{q^2}{4a} - \frac{2q^2}{4a} + r = \frac{-q^2}{4a} + r \] ### Step 3: Relate the roots of \( f(x) \) and \( g(x) \) Given that the roots of \( f(x) = 0 \) are \( \alpha \) and \( \beta \), we have: \[ \alpha + \beta = -\frac{b}{a} \quad \text{and} \quad \alpha \beta = \frac{c}{a} \] For \( g(x) = 0 \), the roots are \( \alpha + \delta \) and \( \beta + \delta \): \[ (\alpha + \delta) + (\beta + \delta) = -\frac{q}{a} \] This implies: \[ \alpha + \beta + 2\delta = -\frac{q}{a} \] Substituting \( \alpha + \beta = -\frac{b}{a} \): \[ -\frac{b}{a} + 2\delta = -\frac{q}{a} \] Thus, \[ 2\delta = \frac{-q + b}{a} \quad \Rightarrow \quad \delta = \frac{-q + b}{2a} \] ### Step 4: Equate the maximum values From the calculations of maximum values: \[ f_{\text{max}} = \frac{-b^2}{4a} + c \] \[ g_{\text{max}} = \frac{-q^2}{4a} + r \] To find the relationship between \( f_{\text{max}} \) and \( g_{\text{max}} \), we can analyze the expressions: \[ f_{\text{max}} = g_{\text{max}} \implies \frac{-b^2}{4a} + c = \frac{-q^2}{4a} + r \] This leads us to conclude that: \[ f_{\text{max}} = g_{\text{max}} \] ### Conclusion Thus, we conclude that \( f_{\text{max}} \) is equal to \( g_{\text{max}} \), which corresponds to option 3.

To solve the problem, we will analyze the functions \( f(x) \) and \( g(x) \) and their maximum values. ### Step 1: Identify the maximum values of \( f(x) \) and \( g(x) \) Given: - \( f(x) = ax^2 + bx + c \) - \( g(x) = ax^2 + qx + r \) ...
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