Question:medium

If the angle between the pair of lines $x^2 - 2cxy - 7y^2 = 0$ is $\frac{\pi}{3}$, then the value of $c^2$ is:

Show Hint

Simplify the fraction inside the angle formula first before squaring to prevent arithmetic mistakes: $\sqrt{3} = \frac{\sqrt{c^2+7}}{3} \implies c^2+7 = 27 \implies c^2 = 20$.

Updated On: May 31, 2026

$20$
$10$
$5$
$15$

Show Solution

The Correct Option is A

Solution and Explanation

Was this answer helpful?

Questions Asked in AP EAPCET exam

Let \[ f(x)=\int \frac{\sqrt{x}}{(1+x)^2}\,dx \quad (x\geq 0) \] Then \[ f(3)-f(1) \] is equal to:

AP EAPCET - 2026
Definite and indefinite integrals

View Solution

Gas is being pumped into a spherical balloon at the rate of $ 30 \, \text{ft}^3/\text{min} $. Then the rate at which the radius increases when it reaches the value $ 15 \, \text{ft} $ is:

AP EAPCET - 2026
Differentiation

View Solution

Let the function $ f(x) $ be defined as $ f(x) = \frac{x - |x|}{x} $, then:

AP EAPCET - 2026
Definite and indefinite integrals

View Solution

If the direction ratios of two lines are given by $ l + m + n = 0 $ and $ mn - 2ln + lm = 0 $, then the angle between the lines is:

AP EAPCET - 2026
3D Geometry

View Solution

If the angle between the pair of lines $x^2 - 2cxy - 7y^2 = 0$ is $\frac{\pi}{3}$, then the value of $c^2$ is:

Show Hint

The Correct Option is A

Solution and Explanation

Top Questions on Coordinate Geometry

Questions Asked in AP EAPCET exam