Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Calculus

Question:

If $y=xy^2+4x^2, $ then $\frac{dy}{dx}$ is equal to __________.

Options:

$2xy+y^2+8x$

$2y+8x$

$\frac{8x+y^2}{1-2xy}$

$\frac{4x^2}{1-xy}$

Correct Answer:

$\frac{8x+y^2}{1-2xy}$

Explanation:

The correct answer is Option (3) → $\frac{8x+y^2}{1-2xy}$

$y=xy^2+4x^2$   $[(uv),=u'v+v'u]$

$⇒\frac{dy}{dx}=y^2+2xy\frac{dy}{dx}+8x$

$⇒\frac{dy}{dx}(1-2xy)=8x+y^2$

$⇒\frac{dy}{dx}=\frac{8x+y^2}{1-2xy}$