The roots of a quadratic equation $ax^2 + bx + c = 0$ are given by:
\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}.\]
Here, $a = 1$, $b = 1$, and $c = -p(p + 1)$. Substituting:
\[x = \frac{-1 \pm \sqrt{1 + 4p(p + 1)}}{2}.\]
This simplifies to:
\[x = -p, \quad x = -(p + 1).\]
Let \( \alpha, \beta \) be the roots of the equation \( x^2 - ax - b = 0 \) with \( \text{Im}(\alpha) < \text{Im}(\beta) \). Let \( P_n = \alpha^n - \beta^n \). If \[ P_3 = -5\sqrt{7}, \quad P_4 = -3\sqrt{7}, \quad P_5 = 11\sqrt{7}, \quad P_6 = 45\sqrt{7}, \] then \( |\alpha^4 + \beta^4| \) is equal to:
Case | Mirror | Focal Length (cm) | Object Distance (cm) |
---|---|---|---|
1 | A | 20 | 45 |
2 | B | 15 | 30 |
3 | C | 30 | 20 |