The surface area of a cube is S(x) = 6x2, where x is the length of the side of each edge of a cube. Restrict the domain to create a one-to-one function. Find and describe the inverse function.

Answer :

Restrict values of  x  to [tex]x \ge 0[/tex].  Then the surface area function is one-to-one and has an inverse.

Write  y  instead of S(x).  Interchange  x  and  y, then solve for  y.

[tex]y=6x^2 \\ x=6y^2 \\ y^2=\frac{x}{6} \\ y=\sqrt{\frac{x}{6}} [/tex]

This function could be used to find the edge of a cube with a given surface area.  For example, if the area is  x = 54, then the edge is [tex]y=\sqrt{\frac{54}{6}} = \sqrt{9} =3 [/tex]

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