Let $\theta_1$ be the angle between two lines $2 x+3 y+$ $c_1=0$ and $-x+5 y+c_2=0$ and $\theta_2$ be the…

Let $\theta_1$ be the angle between two lines $2 x+3 y+$ $c_1=0$ and $-x+5 y+c_2=0$ and $\theta_2$ be the angle between two lines $2 x+3 y+c_1=0$ and $-x+5 y+$ $c_3=0$, where $c_1, c_2, c_3$ are any real numbers : Statement-1: If $c_2$ and $c_3$ are proportional, then $\theta_1=\theta_2$. Statement-2: $\theta_1=\theta_2$ for all $c_2$ and $c_3$.
  1. Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation of Statement-1.
  2. Statement-1 is true, Statement-2 is true; Statement-2 is not a correct explanation of Statement-1.
  3. Statement-1 is false; Statement- 2 is true.
  4. Statement-1 is true; Statement- 2 is false.

Solution

Two lines $-x+5 y+c_2=0$ and $-x+5 y+c_3$ $=0$ are parallel to each other. Hence statement-1 is true, statement-2 is true and statement-2 is the correct explanation of statement-1.

Asked in: JEE Main 2013 (23 Apr Online)

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