# Interactive Math Applets and Calculators

Not only are you surrounded by math, thanks to technology it’s something you can interact with directly. That’s why I’ve created the library of interactive math applets linked to below. These are connected to math content discussed in my books and other writing. I’ll be updating the page often, so come back soon!

## Related to *Everyday Calculus*

#### Trigonometry

How trigonometry can help you get better sleep (see Figure 1.1 in *Everyday Calculus*)

#### Derivatives and Their Applications

Secant and tangent lines; average and instantaneous rates of change (see Figure 2.2 in *Everyday Calculus*)

The mathematics of coffee cooling (see Figures 2.3 and 2.4 in *Everyday Calculus*)

## Related to *The Calculus of Happiness*

How many calories does your body burn each day? (see Equations 1.1-1.2 in *The Calculus of Happiness*)

How many calories does your body burn per minute of exercise? (see Equation 1.4 in *The Calculus of Happiness*)

What’s your maximum heart rate? (see Equation 1.6 in *The Calculus of Happiness*)

How to estimate your Total Daily Energy Expenditure (see Equation 1.8 in *The Calculus of Happiness*)

Calculating the (surprisingly positive) effects of swapping carbs for fats in your diet (see Equation 2.1 in *The Calculus of Happiness*)

Estimating your federal income tax due (see Equation 3.4 in *The Calculus of Happiness*)

Calculating the monthly payment on a loan (including a mortgage) (see Equation 3.10 in *The Calculus of Happiness*)

If you converted your rent payment into a mortgage payment, how much house could you afford? (see Equation 3.11 in *The Calculus of Happiness*)

Calculating how long it’ll take you to pay off a loan (see Equation 3.14 in *The Calculus of Happiness*)

How to retire early with the help of math (see Equation 3.17 in *The Calculus of Happiness*)

Estimating the number of potentially compatible partners in your area (see Equation 5.1 in *The Calculus of Happiness*)

An equation for dividing up something (like pizza) fairly between two people (see Equations 6.7a-6.7b in *The Calculus of Happiness*)

## Related to *The Reducetarian Solution*

How can we estimate the greenhouse gas emissions associated with our diet? (this calculator was referenced in my essay in *The Reducetarian Solution)*