GridMaths is Grid Paper for your screen,
with some really nice extras that make it ideal for exploring Math:
type in any square
lines, boxes & ellipses
step thru edit history
save the trees
more coming soon
Handy for worked Math problems where you need to line up the columns.
Helps you focus on the concepts when doing long division and multiplication.
Getting Started Guide
Tap or click on a square to type there
Type with keys and use arrow keys to move around
pops up the Numeric tap keypad
for lines, boxes and ellipses
goes back to normal text and number entry
Quisinaire Rods and Beans tap pad
choose current Color, Line and Opacity
navigate thru your edits
destroys the preceeding edit
to view other Sheets
adds a new Grid Sheet
Solving the quadratic equation.
Suppose `ax^2+b x+c=0` and `a!=0`.
We first divide by `a` to get `x^2+b/a x+c/a=0`.
Then we complete the square and obtain `x^2+b/a x+(b/(2a))^2-(b/(2a))^2+c/a=0`.
The first three terms factor to give `(x+b/(2a))^2=(b^2)/(4a^2)-c/a`.
Now we take square roots on both sides and get `x+b/(2a)=+-sqrt((b^2)/(4a^2)-c/a)`.
Finally we subtract `b/(2a)` from both sides and simplify :
`x_(1,2)=(-b+-sqrt((b^2 - 4ac)))/(2a)`