SpyAli

bull spread
profit: max(0,S-X1) - Max(0,S-X2) - c1 + c2
splitting up into ranges:
Payoff will be:
S 0
X1 S-X1 - 0 = S-X1
S  X2 - S - X1 - (S-X2) = X2 - X1
Max Profit - will be the X2 - X1 - c1 + c2 (look at the place where there is no S)
Break even:
for breakeven – look at the only payoff situation which has S anywhere in it.
it is where X1 Payoff is S-X1
Profit then is S-X1 - c1 + c2
if this profit is 0 – for a breakeven S=X1+C1 - C2