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bm1957
16th August 2007 - 12:22 PM
Is there a simple way to multiply (x-z)(x-z*) without changing z,z* from polar to cartesian?

Thanks
AlphaNumeric
19th August 2007 - 02:01 PM
(x-z)(x-z*) = x² - x(z+z*) + zz* = x² - 2x.Real(z) + |z|²

If z = a+ib then (x-z)(x-z*) = x² - 2ax + a²+b².

If z = r.e^(it) then (x-z)(x-z*) = x² - 2x.cos(t) + r²
bm1957
19th August 2007 - 08:15 PM
Cheers
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