The implicit relation x^ 2 y+y^ 3 =4 defines a smooth curve consisting of multiple…

MATHEMATICS · Multi-part · AP · Calculus AB · Analytical Applications of Differentiation · Analytical Applications of Differentiation

Problem

The implicit relation

x^{2}y+y^{3}=4

defines a smooth curve consisting of multiple branches. (1) Treat

x

as an implicit function of

y

in a neighborhood where such a representation is valid. Compute

\dfrac{dx}{dy}

and simplify. (2) Determine all points on the curve where the

x

–coordinate could achieve a relative extremum with respect to

y

. Include points where

\dfrac{dx}{dy}=0

and points where

\dfrac{dx}{dy}

is undefined but the curve remains smooth. (3) Using the sign of

\dfrac{dx}{dy}

on appropriate intervals of

y

, classify each point from part (b) as a relative minimum, a relative maximum, or neither for the

x

–coordinate as

y

varies. Provide complete justification. (4) Explain how the orientation of the curve (viewing

x

as a function of

y

rather than

y

as a function of

x

) affects your interpretation of what constitutes a "relative extremum" in this context.