# Playing around with fx-991MS

I have a Math exam coming soon. Thought I should share a few tricks I know with the calculator most of use. First one you probably have encountered: solving a function (say f(x)) when the values of variables are given. I mostly used this while working on problems of Numerical Methods last sem. It is useful for monotonous calculations where you have one function that you don’t constantly want to re-type. Here’s how you go about doing it:

Do you see the A, B, C, D, E, F, X and Y in red? Those are your variables. Surely, these many will suffice in your equation. Assuming f(x, y) = x^2 + y^2 You press ALPHA + ‘)’ [or X] (or any other variable of your choice), then the ‘squaring’ button (x^2) and finally you do the same thing with Y. After that is done, your equation is ready! Press CALC. It prompts you for the values of X and Y respectively. Enter them and your calculator will have the answer for you.

The second trick is ‘Solving for X’. It is similar to the previous method except this is an equation not an expression. So, don’t miss out the ‘=’ in your equation (which can be inserted using ALPHA + CALC [or =]). Assume the equation to be 3X = 39 Type the equation now press SHIFT + CALC [SOLVE] twice. Yes, twice. If you press it once, it will prompt you for the value of X. When you press it twice it solves the equation. It may take time depending on the degree of the equation.