Differentiation Question 168

Question: If $ ax^{2}+2hxy+by^{2}+2gx+2fy+c=0 $ , then $ \frac{dy}{dx}= $

Options:

A) $ -\frac{ax+hy+g}{hx-by+f} $

B) $ \frac{ax+hy+g}{hx-by+f} $

C) $ \frac{ax-hy-g}{hx-by-f} $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

$ ax^{2}+2hxy+by^{2}+2gx+2fy+c=0 $

Differentiating w.r.t. x of y, we get $ 2ax+2h( y+x\frac{dy}{dx} )+2by\frac{dy}{dx}+2g+2f\frac{dy}{dx}=0 $

$ \therefore \frac{dy}{dx}(2hx+2by+2f)=-(2ax+2hy+2g) $

or $ \frac{dy}{dx}=-\frac{(ax+hy+g)}{(hx+by+f)} $ .