Question:medium

The value of the angle between two straight lines is \(y = (2 - \sqrt{3})x + 5\) and \(y = (2 + \sqrt{3})x - 7\) is

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Use \(\tan \theta\) formula for angle between two lines using slopes.
Updated On: Jun 16, 2026
  • \(30^\circ\)
  • \(60^\circ\)
  • \(45^\circ\)
  • \(90^\circ\)
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The Correct Option is B

Solution and Explanation

To find the angle between the two lines given by the equations \(y = (2 - \sqrt{3})x + 5\) and \(y = (2 + \sqrt{3})x - 7\), we can use the formula for the angle between two lines. If the equations of the lines are \(y = m_1x + c_1\) and \(y = m_2x + c_2\), then the angle \(\theta\) between the two lines can be calculated using the following formula:

\(\theta = \tan^{-1}\left(\frac{|m_2 - m_1|}{1 + m_1 m_2}\right)\)

Here, \(m_1 = 2 - \sqrt{3}\) and \(m_2 = 2 + \sqrt{3}\). Let's plug these values into the formula:

\(\theta = \tan^{-1}\left(\frac{|(2 + \sqrt{3}) - (2 - \sqrt{3})|}{1 + (2 - \sqrt{3})(2 + \sqrt{3})}\right)\)

Simplifying the numerator:

\(= \tan^{-1}\left(\frac{|2 + \sqrt{3} - 2 + \sqrt{3}|}{1 + (2^2 - (2 \times 2\sqrt{3}) + (\sqrt{3})^2)}\right)\)

\(= \tan^{-1}\left(\frac{2\sqrt{3}}{1 + (4 - 4 + 3)}\right)\)

\(= \tan^{-1}\left(\frac{2\sqrt{3}}{1 + 3}\right)\)

\(= \tan^{-1}\left(\frac{2\sqrt{3}}{4}\right)\)

\(= \tan^{-1}\left(\frac{\sqrt{3}}{2}\right)\)

We know from trigonometry that:

\(\tan(60^\circ) = \sqrt{3}\), therefore the angle between the two lines is:

\(\theta = 60^\circ\)

Thus, the correct answer is \(60^\circ\).

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