### Agile Algebra

Observe symmetries and engage the power of substitution to solve complicated equations.

### Graphs of Changing Areas

Use graphs to gain insights into an area and perimeter problem, or use your knowledge of area and perimeter to gain insights into the graphs...

# Complex Partial Fractions

##### Age 16 to 18 Challenge Level:
Just use the usual methods for partial fractions and factorise $x^2+1$ into $(x+i)(x-i)$.