A line \( L \) passing through the point \( (2,0) \) makes an angle \( 60^\circ \) with the line \( 2x - y + 3 = 0 \). If \( L \) makes an acute angle with the positive X-axis in the anticlockwise direction, then the Y-intercept of the line \( L \) is?
We need to find the Y-intercept of the line \( L \) that passes through the point \( (2,0) \) and makes a \( 60^\circ \) angle with the line \( 2x - y + 3 = 0 \). The equation of line \( 2x - y + 3 = 0 \) can be rewritten as \( y = 2x + 3 \), giving it a slope \( m_1 = 2 \).
Let the slope of line \( L \) be \( m \). Using the formula for the angle between two lines, we have:
\(\tan^{-1}\left(\left|\frac{m - m_1}{1 + mm_1}\right|\right) = 60^\circ\)
Substituting, we get:
\(\left|\frac{m - 2}{1 + 2m}\right| = \sqrt{3}\)
This results in two equations:
\(\frac{m - 2}{1 + 2m} = \sqrt{3}\) and \(\frac{m - 2}{1 + 2m} = -\sqrt{3}\)
Solving the first equation:
\(m - 2 = \sqrt{3} + 2\sqrt{3}m\)
\(m - 2\sqrt{3}m = 2 + \sqrt{3}\)
\(m(1 - 2\sqrt{3}) = 2 + \sqrt{3}\)
\(m = \frac{2 + \sqrt{3}}{1 - 2\sqrt{3}}\)
Rationalize the denominator:
\(m = \frac{(2 + \sqrt{3})(1 + 2\sqrt{3})}{(1 - 2\sqrt{3})(1 + 2\sqrt{3})}\)
\(m = \frac{2 + 4\sqrt{3} + \sqrt{3} + 6}{1 - 12}\)
\(m = \frac{8 + 5\sqrt{3}}{-11}\)
\(m = -\frac{8}{11} - \frac{5\sqrt{3}}{11}\)
We need the line to make an acute angle with the positive X-axis, so its slope should be positive:
The correct slope \( m = \frac{-8 - 5\sqrt{3}}{11} \).
The equation of line \( L \) is:
\(y - 0 = m(x - 2)\)
Substituting for \( m \) and rearranging gives:
\(y = \left(\frac{-8 - 5\sqrt{3}}{11}\right)x + \frac{16 + 10\sqrt{3}}{11}\)
The Y-intercept is thus \(\frac{16 - 10\sqrt{3}}{11}\).
| List-I | List-II | ||
|---|---|---|---|
| (A) | $f(x) = \frac{|x+2|}{x+2} , x \ne -2 $ | (I) | $[\frac{1}{3} , 1 ]$ |
| (B) | $(x)=|[x]|,x \in [R$ | (II) | Z |
| (C) | $h(x) = |x - [x]| , x \in [R$ | (III) | W |
| (D) | $f(x) = \frac{1}{2 - \sin 3x} , x \in [R$ | (IV) | [0, 1) |
| (V) | { -1, 1} | ||
| List I | List II | ||
|---|---|---|---|
| (A) | $\lambda=8, \mu \neq 15$ | 1. | Infinitely many solutions |
| (B) | $\lambda \neq 8, \mu \in R$ | 2. | No solution |
| (C) | $\lambda=8, \mu=15$ | 3. | Unique solution |
A line \( L \) intersects the lines \( 3x - 2y - 1 = 0 \) and \( x + 2y + 1 = 0 \) at the points \( A \) and \( B \). If the point \( (1,2) \) bisects the line segment \( AB \) and \( \frac{a}{b} x + \frac{b}{a} y = 1 \) is the equation of the line \( L \), then \( a + 2b + 1 = ? \)
If the slope of one line of the pair of lines \( 2x^2 + hxy + 6y^2 = 0 \) is thrice the slope of the other line, then \( h \) = ?