Notes on using Trial and Error1dp.xls

This worksheet can be used to introduce the topic of solving Equations by Trial and Error, or as practice and revision later on.

The start of the range of x values and the cubic equation can be changed using the values in the bright green cells x, a, b, c, d, at the top. All other cells are locked and protected.

The worksheet will find to 1 decimal places the first root in the range.

To find other roots just change the starting value so that the root you want is the first one in the range.

The presence of a root in an interval is shown by highlighting where there is a change from A to B (Above or Below the value on the right hand side of the equation.

I use this projected on to a white board when explaining the topic and to sequence the students through the stages asking questions, getting them to do the “next bit” and then checking until they have got it.

It is also useful to quickly allow students to check answers and working for the different stages of a problem or indeed for the teacher when setting or correcting questions.

There are buttons so that the display can be zoomed in on one table at a time for easy reading on a whiteboard.