ExamBro
ExamBro
MHT CET · Maths · Application of Derivatives

If the normal to the curve \(y=f(x)\) at the point \((3,4)\) makes and angle \(\left(\frac{3 \pi}{4}\right)^{\mathrm{C}}\) with positive \(\mathrm{X}\)-axis, then \(f^{\prime}(3)\) is equal to

  1. A \(-1\)
  2. B \(1\)
  3. C \(\frac{4}{3}\)
  4. D \(-\frac{3}{4}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(1\)

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \text { Slope of normal }=\frac{-1}{f^{\prime}(x)} \\ & \Rightarrow \tan \left(\frac{3 \pi}{4}\right)=\frac{-1}{f^{\prime}(3)} \\ & \Rightarrow-1=\frac{-1}{f^{\prime}(3)} \\ & \Rightarrow f^{\prime}(3)=1\end{aligned}\)