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JEE MainMathematicsEasyApplication of derivatives

If θ denotes the acute angle between the curves, y=10-x^2 and
y=2+x^2 at a point of their intersection, then |tanθ | is equal

Show answer and solution
y=x2+2&y=10−x2 y = x^{2} + 2\& y = 10 - x^{2}\ meet at (±2,6)( \pm 2,6)
dydx=2x \frac{dy}{dx} = 2x\ for first curve and dydx=−2x \frac{dy}{dx} = - 2x\ for
second

hence slope are 4 and -4

 so ∣tanθ∣=∣4−(−4)1+4(−4)∣=815\ so\ |tan\theta| = \left| \frac{4 - ( - 4)}{1 + 4( - 4)} \right| = \frac{8}{15}

Source: Grass-G / M-28 Mathematics Paper FST 16 Jan.docx

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