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Translate JS into math (multiple variables defined)

Michael Adegoke

I have this code I am trying to translate into maths

var Top=1+MonthlyInterestRate;

Top=Math.pow(Top,npr);'

Top=MonthlyInterestRate*Top;

var Bottom=1+MonthlyInterestRate;

Bottom=Math.pow(Bottom,npr)-1;

var MonthlyPayment=(PrincipalBalance*(Top/Bottom)).toFixed(2);

My basic problem is that the var ‘top’ is declared 3 times, so I don’t know how to reflect it mathematically.

var bottom is also declared twice, which value will be the final?

the first variable or the second?

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Answer

JavaScript is imperative, instructions are executed from top to bottom. Here’s what happens, in order:

  1. Top equals 1 + MonthlyInterestRate,
  2. Top is set to Top to the power of npr
  3. Top is set to Top multiplied by MonthlyInterestRate
  4. Bottom equals 1 + MonthlyInterestRate,
  5. Bottom is set to Bottom to the power of npr minus 1
  6. then finally the result of Top divided by Bottom is multiplied by PrincipalBalance

A mathematical equation would be something along the lines of:

where a equals to PrincipalBalance, b equals to MonthlyInterestRate and c equals to npr

equation