The angle of intersection between the curves $y=4-x^2$ and $y=x^2 $ is :
Answer & explanation
Correct answer: option 4
The correct answer is option (4) → $\tan^{-1}\frac{4\sqrt{2}}{7}$
$y=4-x^2$ ...(1)
$y=x^2$ ...(2)
finding intersection point
$4-x^2=x^2⇒x^2=2⇒x=±\sqrt{2}$
$y=2$
from (1) $\frac{dy}{dx}=m=-2x$
from (2) $\frac{dy}{dx}=2x=n$
angle $\tan θ=\left|\frac{m-n}{1+mn}\right|$ at $x=\sqrt{2}$
$θ=\tan^{-1}\left|\frac{2\sqrt{2}+2\sqrt{2}}{1+(-8)}\right|$
$=\tan^{-1}\frac{4\sqrt{2}}{7}$
even with $x = -\sqrt{2}$
$θ=\tan^{-1}=\frac{4\sqrt{2}}{7}$