Calculating with Bounds

Will see show the amount of error in a calculation, if what is the amount of error when is calculated? The vertical black line can be moved to change the value of and the slider moved to change the value of . The red curve is , the black curve is and the blue curve is . Look at different values of and and see how errors are changing following a calculation. Also look at different function such as . What about the percentage error, how does that change?
Created by Dr GJ Daniels.