Rent or buy: a break-even model

Workflow 5 steps, run in order in one session. Every step was executed against the engine and the output below is what it produced.

Step 1

rentCost[m_] := rent m
buyCost[m_] := closing + (payment + maintenance) m

No output - this step sets something up for the next one.

Step 2

breakEven = First[Solve[rentCost[m] == buyCost[m], m]]

Output

{m -> closing/(-maintenance - payment + rent)}

Step 3

D[m /. breakEven, rent]

Output

-(closing/(-maintenance - payment + rent)^2)

Step 4

assumptions = {closing -> 40000, maintenance -> 500, rent -> 2600, payment -> 1900};
monthsToBreakEven = N[m /. breakEven /. assumptions]

Output

200.

Step 5

Plot[{rentCost[m] /. assumptions, buyCost[m] /. assumptions}, {m, 0, 300}]

Output

-Graphics-

Rent or buy: a break-even model

Functions used