class 12 maths application of derivatives

Find the points on the curve $y = {x^3}$ at which the slope of the tangent is equal to the $y$-coordinate of the point.

VAVidaara Admin Asked 8d ago 0 views 0 answers
📘 Application of Derivatives NCERT Ex. 6.3, Q.17,Page 212 SA

Find the points on the curve $y = {x^3}$ at which the slope of the tangent is equal to the $y$-coordinate of the point.

Official Solution

VVidaara Team ✓ Verified solution NCERT & Exemplar

We have,
$y = {x^3}$ …(i)

Differentiating (i), w.r.t. $x$ , we get
$\cfrac{{dy}}{{dx}} = 3{x^2}$
Since, it is given that slope is equal to the $y -$coordinate of the point

$\therefore \cfrac{{dy}}{{dx}} = y \Rightarrow 3{x^2} = y$ (using (ii))
$\Rightarrow 3{x^2} = {x^3} \Rightarrow {x^2}\left( {3 - x} \right) = 0 \Rightarrow x = 0$ or $x = 3$ (using (i))

When $x = 0$, then from (i)$y = 0$
When $x = 3$, then from (i), $y = {3^3} = 27$

Therefore the required points are $(0,0)$ and $(3,\;27)$.

View the full step-by-step solution page & related questions →

Community Answers (0)

Log in to post your own answer or join the discussion.

Discussion (0)

No comments yet — start the discussion.

← Back to all questions