Please help me write a php code

Question

# is written based on this normal distribution formula. μ is the number of days 1 divided by 2, σ is the root of the number of days, the total number multiplied by f (x) is the daily increment, x is the number of days

, and the final output is the summation value.

For example, the data I want to display on the fifth day page is Z=f(1) f(2) f(3) f(4) f(5)