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Let x =2 \sqrt{2}\cos\theta, \; y =2 \sqrt{2}\sin\theta and x =2 t, \; y =\frac{2}{t} are two curves then there curves in first quadrant 

  • Option 1)

    intersect at \frac{\pi}{6}

  • Option 2)

    Touch each other

  • Option 3)

    intersect at \frac{\pi}{}4

  • Option 4)

    intersect at \frac{\pi}{}3

 

Answers (1)

best_answer

As we have learened

Condition for the two curves to touch in parametric form -

\frac{g'_{x}}{g'_{y}}=\frac{f'_{x}}{f'_{y}}

- wherein

Where

x=f(t)

y=f(t)

 

 For point of intersection or touching i.e common point : 2\sqrt2 \cos \theta =2t   and 

2\sqrt2 \sin \theta =2/t

\Rightarrow t= \sqrt2 \cos \theta    and  2\sqrt2 \sin \theta \times \sqrt2 \cos \theta = 2\Rightarrow \sin 2\theta

\Rightarrow \theta = \pi /4  for first quadrant common point and t =1

 \therefore  point is (2,2)

\frac{fx^{1}}{fy^{1}}= \frac{-2 \sqrt 2 \sin \theta }{ 2\sqrt 2 \cos\theta }= - \tan \theta \Rightarrow \frac{fx^{1}}{fy^{1}}   at \theta = \pi /4    is -1 

 

\frac{gx^{1}}{gy^{1}}= \frac{2}{-2/t^{2}}= -t^{2}\Rightarrow \frac{gx^{1}}{gy^{1}}    at t= 1 is -1 

 

\frac{fx^{1}}{fy^{1}}=\frac{gx^{1}}{gy^{1}}    so curves touch each  other at common point 

 

 

 

 


Option 1)

intersect at \frac{\pi}{6}

Option 2)

Touch each other

Option 3)

intersect at \frac{\pi}{}4

Option 4)

intersect at \frac{\pi}{}3

Posted by

Himanshu

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