If the normal to the curve $y=f(x)$ at the point (3, 4) makes an angle $\frac{3\pi }{4}$ with the positive x-axis then $f'(3)=$ _________.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1
$y=f(x)$ Point (3, 4)
slope of normal = $\tan\frac{3π}{4}=-1$
slope of normal = $\frac{-1}{f'(x)}$
so basically $\frac{-1}{f'(3)}=-1$
$⇒f'(3)=1$