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If \theta denotes the acute angle between the curves, y = 10-x^2 and y = 2 +x^2 at a point of their intersection, then |\tan\theta| is equal to:

  • Option 1)

    \frac{4}{9}

  • Option 2)

    \frac{8}{15}

  • Option 3)

    \frac{7}{17}

  • Option 4)

    \frac{8}{17}

Answers (1)

best_answer

 

Angle of intersection of two curves -

The angle of intersection of two curves is the angle subtended between the tangents at their point of intersection.Let  m1  &  m2 are two slope of tangents at intersection point of two curves then

tan\theta=\frac{[m_{1}-m_{2}]}{1+m_{1}m_{2}}

- wherein

where \theta is angle between two curves tangents.

 

Given curves are 

y=10-x^{2}  and   y=2+x^{2}

First find point of intersection 

P(2,6)

Also m_{_{1}}=\frac{\mathrm{d} y}{\mathrm{d} x}|_{P(2,6)}=-2x=-4

and  m_{_{2}}=\frac{\mathrm{d} y}{\mathrm{d} x}|_{P(2,6)}=2x=4

\therefore \left | \tan \theta \right |=\left | \frac{m_{1}-m_{2}}{1+m_{1}m_{2}} \right |=\left | \frac{-4-4}{1+(-4)(4)} \right |=\frac{8}{15}


Option 1)

\frac{4}{9}

Option 2)

\frac{8}{15}

Option 3)

\frac{7}{17}

Option 4)

\frac{8}{17}

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