hey guys what are your answer for these 2 qns cheers (1 Viewer)

dinesh97 · Mar 29, 2015

need help with these 2 qns

Ekman · Mar 29, 2015

Q1)

$$ Let u$=y $ and v$= \cos(\frac{1}{y})$

$\therefore $ Differential of the LHS is:$ \frac{dy}{dx}(\cos(\frac{1}{y}) + \frac{\sin(\frac{1}{y})}{y})$

$$ Differential of the LHS is:$ 4+4\frac{dy}{dx}$

$$Hence: $ \frac{dy}{dx}(\cos(\frac{1}{y}) + \frac{\sin(\frac{1}{y})}{y}) =4+4\frac{dy}{dx}$

$\frac{dy}{dx} = \frac{4}{(\cos(\frac{1}{y}) + \frac{\sin(\frac{1}{y})}{y})-4}$

Therefore answer is the Fourth one

Q2)

$\sec(9y) = \frac{1}{cos(9y)}$

$$ Differential of the RHS: $ 9\frac{dy}{dx}\sec(9y)\tan(9y)$

$$ Differential of the LHS: $ 1$

$\therefore \frac{dy}{dx} = \frac{1}{9}\cos(9y)\cot(9y)$

Therefore the answer is the First one

braintic · Mar 29, 2015

Ekman said:
Differential

You mean derivative

dy is the differential.

hey guys what are your answer for these 2 qns cheers (1 Viewer)

dinesh97

New Member

Ekman

Well-Known Member

braintic

Well-Known Member

Users Who Are Viewing This Thread (Users: 0, Guests: 1)