Re: HSC 2016 Complex Numbers Marathon
That method is great cause you didn't even need the assumption ow lies on sum of u1 and u2 as you followed it using its construction
Re: HSC 2016 Complex Numbers Marathon
The best approach to these harder questions is to use the answer and think given what you have what you need to prove, since OW is diameter prove |w|=2/|u1+u2| and a more advanced method is play with that result and you get prove |w(u1+u2)|=2 which looks...
Re: HSC 2016 Complex Numbers Marathon
Sub z=w into each tangent equation since that's the intersection point. Then add each equation and you'll notice if you factorise correctly you get sum of two conjugates
Re: HSC 2016 Complex Numbers Marathon
Another problem is the centre of the circle is not the midpoint of the chord, it's impossible. I'll give you a hint to solve it really easily in a few seconds. The intersection of the tangents is the point w so if you let OW be the complex number w you can...
Re: HSC 2016 Complex Numbers Marathon
NEW
Prove that if a, b and c are concyclic and the circle passes through the origin then 1/a, 1/b and 1/c are collinear. Where a, b and c are complex and in quadrant one.
Math Man is back and seeing the different marathons thought different topic themed marathons seems like a good idea.
I would love to do mechanics but it's too early for that and I love complex numbers!
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1. Once a question has been answered you can ask a new question.
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working out is, complete the square on the bottom as:
(x^{2}+2x+1)cos^{2}x-2(1+x)sinxcosx +sin^{2}x -cos^{2}x-sin^{2}x= \\ \\ ((x+1)cosx-sinx)^{2}-1
and we note that
\frac{d}{dx} (x+1)cosx-sinx= -(1+x)sinx
so the integral is in the form
\int \frac{f'(x)}{f^{2}(x)-1}dx...