I learnt Black-Scholes formula before, wot I learnt is jst the very standard one in continuous process.

But the formula the text book use is a bit different, especially for use of the exercise price which the text book is using annual compounding, but standard formula usually use continuous compounding.

Since I learnt it before, so jst a bit confuse which one i should use or they both ok for this course.

[NEAS: The formula is generally written with continuous compounding. Since most college students are not comfortable with continuous compounding, the textbook uses annual effective yields. As long as the yields are properly adjusted (by taking the logarithms or exponentiating), the result is the same. The final exam questions for this course use the formula in the textbook.