Hard INTEGER +4 / -1 PYQ · JEE Mains 2024

Let $\alpha, \beta \in \mathbf{N}$ be roots of the equation $x^2-70 x+\lambda=0$, where $\frac{\lambda}{2}, \frac{\lambda}{3} \notin \mathbf{N}$. If $\lambda$ assumes the minimum possible value, then $\frac{(\sqrt{\alpha-1}+\sqrt{\beta-1})(\lambda+35)}{|\alpha-\beta|}$ is equal to :

Answer (integer) 60

Solution

<p>$$\begin{aligned} & x^2-70 x+\lambda=0 \\ & \alpha+\beta=70 \\ & \alpha \beta=\lambda \\ & \therefore \alpha(70-\alpha)=\lambda \end{aligned}$$</p> <p>Since, 2 and 3 does not divide $\lambda$</p> <p>$\therefore \alpha=5, \beta=65, \lambda=325$</p> <p>By putting value of $\alpha, \beta, \lambda$ we get the required value $60$.</p>

About this question

Subject: Mathematics · Chapter: Complex Numbers and Quadratic Equations · Topic: Complex Numbers and Argand Plane

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