In today's class we looked at how you can use a function to solve a related function.
Using graphs of functions to find the roots of a polynomial is a key skill.
When you graph a function, you find the output values for a selection of discreet input values.
When you join the dots with a smooth curve you are extrapolating the output values of the input values in between. That is why we graph functions.
Wherever your line crosses the x-axis, the output value is 0 - don't forget equation of the x-axis is y=0. So you can use these points to work out the roots of a cubic equation.
We looked at the 1999 q8 question on functions. This included working out a related function. Make sure you do this question and are able to follow it.
When you split the related cubic function into the original cubic and a related linear function, you can work out the roots of the related function by reading the points of intersection from your graph.
Other points on functions which you need to know are mentioned in the 1 page overview.
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