Applications Of Derivatives Question 42
Question: How many tangents are parallel to x-axis for the curve $ y=x^{2}-4x+3 $ -
Options:
A) 1
B) 2
C) 3
D) No tangent is parallel to x-axis
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Let $ y=x^{2}-4x+3 $ Differentiate both sides w.r.t. -x- $ \frac{dy}{dx}=2x-3 $ So, slope $ =2x-3 $ Since, tangent is $ \parallel $ to x = axis
$ \therefore $ slope = 0
$ \Rightarrow \frac{dy}{dx}=0\Rightarrow 2x-3=0\Rightarrow x=\frac{3}{2} $
$ \Rightarrow $ one tangent
BETA
