How do you calculate effective interest rates?

That depends on what you DO know. You might consider asking again, being more specific about what information you have. For example, if you know the amount of interest, the principal, and the length...

derivation of this formula r=(1+i/m)m-1

if i could rearange the alphabet i would put u and i together

The simple interest rate of a number is represented by the following formula: i = (T / P) - 1Where:i = interest rateT = total of all paymentsP = principal amountFor example, what is the interest rate...