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The tangent of angle between the lines whose intercepts on the axes are a, – b and b, – a, respectively, is ______.

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Question

The tangent of angle between the lines whose intercepts on the axes are a, – b and b, – a, respectively, is ______.

Options

  • `(a^2 - b^2)/(ab)`

  • `(b^2 - a^2)/2`

  • `(b^2 - a^2)/(2ab)`

  • None of these

MCQ
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Solution

The tangent of angle between the lines whose intercepts on the axes are a, – b and b, – a, respectively, is `(b^2 - a^2)/(2ab)`.

Explanation:

First equation of line having intercepts on the axes 

a, – b is `x/a - y/b` = 1

⇒ bx – ay = ab   ......(i)

Second equation of line having intercepts on the axes

b, – a is `x/b - y/a` = 1

⇒ ax – by = ab   .....(ii)

Slope of equation (i) m1 = `b/a`

Slope of equation (ii) m2 = `a/b`

∴ tan θ = `|(m_1 - m_2)/(1 + m_1m_2)|`

= `(b/a - a/b)/(1 + a/b  b/a)`

= `(b^2 - a^2)/(2ab)`

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Chapter 10: Straight Lines - Exercise [Page 180]

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NCERT Exemplar Mathematics Exemplar [English] Class 11
Chapter 10 Straight Lines
Exercise | Q 26 | Page 180

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