binomial tree

Repeat 1–3 for puts.
Exercise 3
Repeat 1 for an initial stock price of S = $11, all other parameters being the same.
Exercise 1
Approximate the value of a European call struck at $10 on a stock with initial stock price $10. The risk-free rate of interest is 5% and the stock volatility is 20%, both in annual units. Use a binomial tree with a 1, 2, 3, 4, and 5 branching opportunities. (You will need to adjust u and d accordingly; they will get smaller as the number of branching points on the tree increases.) What do you see as the number of branching points increases?