Match List-I with List-II. Find the derivatives from List-I.
| List-I | List-II | ||
| (A) | $y=\sqrt{sinx+y}$ | (I) | $\frac{-sinx}{1+cosy}$ |
| (B) | $siny=xsin (a+y)$ | (II) | $\frac{cosx}{2y-1}$ |
| (C) | $y+siny=cosx$ | (III) | $\frac{-1}{sin^2(x+y)}$ |
| (D) | $y=tan(x+y)$ | (IV) | $\frac{sin^2(a+y)}{sina}$ |
Choose the correct answer from the options given below :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(II),(B)-(IV),(C)-(I),(D)-(III)
(A) $y=\sqrt{\sin x+y}$
so $y^2=\sin x+y$
differentiating wrt (x)
$2y\frac{dy}{dx}=\cos x+\frac{dy}{dx}$
so $\frac{dy}{dx}=\frac{\cos x}{2y-1}$ (II)
(B) $\sin y= x\sin(a+y)$
$x=\frac{\sin y}{\sin(a+y)}$ differentiating wrt (y)
$\frac{dx}{dy}=\frac{(\cos y\sin(a+y)-\cos(a+y)\sin y}{\sin^2(a+y)}=\frac{\sin(y)}{\sin^2(a+y)}$
so $\frac{dy}{dx}=\frac{\sin^2(a+y)}{\sin(y)}$ (IV)
(C) $y+\sin y=\cos x$
differentiating wrt (x)
$\frac{dy}{dx}=(1+\cos y)=-\sin x⇒\frac{dy}{dx}=\frac{-\sin x}{1+\cos y}$ (I)
(D) $y=\tan(x+y)$ ...(1)
so $\tan^{-1}y=x+y$
differentiating wrt y
$\frac{1}{1+y^2}=\frac{dx}{dy}+1$ so $\frac{dy}{dx}=-\frac{(1+y^2)}{y^2}$
$⇒\frac{dy}{dx}=-\frac{(1+\tan^2(x+y))}{\tan^2(x+y)}$
$=\frac{-\sec^2(x+y)}{\tan^2(x+y)}$
$=\frac{-1}{\sin^2(x+y)}$ (III)