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Thats a bit rough putting binomial expansion in complex numbers. Wouldn't have thought of that. (I get what they mean by " as a polynomial in cos theta now"). Well... i guess if i couldn't remember binomial expansion I could do it the long way lol. (Thanks for your help again!!!)

This question doesn't seem like it's in english! I might have a shot at the answer if I understand the question. The question is: By applying de Moivre's theorem and by also expanding (cos(theta) + i sin(theta))^5, express cos(5theta) as a polynomial in cos(theta). I have no idea what...

I usually do it in pencil and then go over it in pen.

Cool i think i get it now. I just didn't figure that the some of roots and products of roots thing would work seeing that y is a variable, but i guess it does. (I originally thought it only worked for when y = 0). Funny, I don't think i ever learnt that. Maybe I forgot... pre HSC stress. Once...

Ahhhhhhh, of course (stupid me). Thanks. (I take it when you say almost, you mean where x = 2)

I need help in understanding how to do the 2003 maths extension 2 question 3 part (c). I generally know how to do volumes of solids of revolution, however I don't know what to do for this question because there are two possible x values or each y value and the question requires you to find the...