What is (5+3i)*(3+5i)
The idea here is to explain to the student that i^2=-1, and to expand and simplify the brackets in question just like they would with simple algebra. Therefore:
(5+3i)*(3+5i)=15+25i+9i+15i^2=15+34i-15=34i
Students can often multiply out the brackets correctly, but then they are not sure what to do with term involving "i^2". Confusion is even bigger if there are minus signs floating around.
SK
Related Maths A Level answers
All answers ▸We have the curve f(x) = (x^2-5x)(x-1)+ 3x. Sketch the graph y=f(x), making sure to plot the co-ordinates where the curve meets the axes.
How should I go about solving a quadratic equation?
Integrate (x+2)/((x+5)(x-7)) using partial fractions between the limits 5 and -2, giving your answer to 3sf
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