Recently my daughter did her homework and came to me to help her. One part of the task was to calculate the area of x^4 + x^3 - 2*x^2 in the interval of 0 and 1. The indefinive integration is x^5/5 + x^4/4 - 2*x^3/3 (see here). Wolfram Alpha claims that the numerical result is -13/60 which approximates to -2.16667. Her Casio FX-991ES calculator gives a totally different result of -1.xxx like that. Now I was unsure whom to blame. I cannot imagine that my Wolfram Alpha (Mathematica) calculates wrong. Then I opened my drawer and took out my good old HP 48G which I used a long time ago when I studied. Let's screenshots talk: And now the result |