HP 40g hp 39g+ (39g & 40g)_mastering the hp 39g+_English_E_F2224-90010.pdf - Page 284

APPENDIX A: WORKED EXAMPLES The examples which follow are intended to illustrate the ways in which the calculator can be used to help solve some typical problems. In some cases more than one method is shown. Sometimes these problems are quoted elsewhere in the book and repeated here for convenience. Finding the intercepts of a quadratic Find the x intercepts of the quadratic equation g(x) = 2x2 + 2x −1 Method 1 - Using the QUAD function in HOME. This method is shown right, using the key in the bottom view. The advantage of doing it this way is that the answer is given in the same form that you would see it if you used the Quadratic formula. Just the result, edit and square the decimal part to find the value of the discriminant. The 'S1' is the calculator's version of the ± sign. Just the result and remove the S1 to obtain the positive solution, replacing the + with a - to obtain the other. This method is only of use if the question said "Show working" because it doesn't give the answer directly. If you need the result in surd form then copy just the decimal part and square it. Method 2 - Using the Function aplet. Shown right. Enter the function into the SYMB view, use the VIEWS key and choose 'Decimal'. If the axes don't suit, then use the options. Now use the option of Root to find the two roots. One result is shown. 284