+91-8076753736[email protected]
logo
logo
-->

Application Of Derivatives

Question
CBSEENMA12035209
Wired Faculty App

Find out on the curve y = x2 – x – 8 at which tangent is parallel to x-axis. Also find the equation of tangent line.

Solution

The equation of curve is
                          y = x2 – x – 8                                    ...(1)
therefore space space space space space space space space space dy over dx space equals space 2 straight x minus 1 because space space space space space space space tangent space is space parallel space to space straight x minus axis therefore space space space space space space space space space dy over dx space equals space 0 space space space space space rightwards double arrow space space space space 2 straight x minus 1 space equals space 0 space space space space rightwards double arrow space space space space straight x space equals space 1 half Putting space straight x space equals space 1 half space in space left parenthesis 1 right parenthesis comma space we space get space space space space space space space space space space space space space space space space space space space space space space space space straight y space equals space 1 fourth minus 1 half space minus 8 space equals space fraction numerator 1 minus 2 minus 32 over denominator 4 end fraction space equals space minus 33 over 4 therefore space space space space point space is space open parentheses 1 half comma space space space space minus 33 over 4 close parentheses. The space equation space of space tangent space line space is space space space space space space space space space space space space straight y space equals space minus 33 over 4 space space space or space space 4 straight y space equals space minus 33 space space space space space or space space space 4 straight y plus 33 space equals space 0

Some More Questions From Application of Derivatives Chapter

The radius of a circle is increasing uniformly at the rate of 4 cm per second Find the rate at which the area of the circle is increasing when the radius is 8 cm.

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation