Question

Find the slope of the tangent and the normal to the following curve at the indicted point  y = (sin 2x + cot x + 2)² at x = π/2 ?

Answer 1

\[ y = \left( \sin 2x + \cot x + 2 \right)^2 \]

\[ \Rightarrow \frac{dy}{dx} = 2 \left( \sin 2x + \cot x + 2 \right) \left( 2\cos 2x - \ cose c^2 x \right)\]

\[\text { Now,} \]

\[\text { Slope of the tangent }= \left( \frac{dy}{dx} \right)_{x = \frac{\pi}{2}} \]

\[=2\left[ \sin 2\left( \frac{\pi}{2} \right) + \cot \left( \frac{\pi}{2} \right) + 2 \right] \left[ 2\cos 2\left( \frac{\pi}{2} \right) - {cosec}^2 \left( \frac{\pi}{2} \right) \right]\]

\[ = 2 \left( 0 + 0 + 2 \right) \left( - 2 - 1 \right)\]

\[ = - 12\]

\[\text { Slope of the normal }=\frac{- 1}{\left( \frac{dy}{dx} \right)_{x = \frac{\pi}{2}}}=\frac{- 1}{- 12}=\frac{1}{12}\]