Question

$Ify=sinxandz=5,then\frac{dy}{dz}$ = _____

• A. cos x
• B. –cosx
• C. 5
• D. Does not exist

Answer 1

The correct option is D Does not exist

We know that $\frac{dy}{dz}=\frac{\frac{dy}{dx}}{\frac{dz}{dx}}.Here\frac{dy}{dx}=cosxand\frac{dz}{dx}=0$ (since it’s a constant function)
So denominator of $\frac{dy}{dz}$ becomes zero and hence $\frac{dy}{dz}$ does not exist.