<![CDATA[solving system of equations produce complex numbers 2]]>
https://help.geogebra.org/topic/solving-system-of-equations-produce-complex-numbers-2
Wed, 27 Feb 2019 21:58:41 +0000Tue, 26 Feb 2019 19:52:05 +0000Zend_Feed<![CDATA[Does this mean that if I have equations with constansts cos(2a), sin(2a) and a, there is a possibility that I get complex roots? Sorry, yes]]>
https://help.geogebra.org/topic/solving-system-of-equations-produce-complex-numbers-2#comment-256572
Wed, 27 Feb 2019 21:58:41 +0000<![CDATA[I can undertand that this can very easily be solved without a computer. My question was why. Does this mean that if I have equations with constansts cos(2a), sin(2a) and a, there is a possibility that I get complex roots? Thanks Mike telling about the Simplify and trigexpand M]]>
https://help.geogebra.org/topic/solving-system-of-equations-produce-complex-numbers-2#comment-256564
Wed, 27 Feb 2019 17:33:51 +0000<![CDATA[maybe because of the entry mode (use of cos and sin) try u = cos(a), v = sin(a) and linearise cos(2a) and sin(2a) before using ratkaise but it's better to solve with just a pen because this is just two lines]]>
https://help.geogebra.org/topic/solving-system-of-equations-produce-complex-numbers-2#comment-256516
Tue, 26 Feb 2019 20:16:39 +0000<![CDATA[This seems OK: Solve({(-3sin(a) + y = (-3a + x) cos(a)),TrigExpand((-cos(2a) + y = -2 (-a + x) sin(2a)))},{x,y})]]>
https://help.geogebra.org/topic/solving-system-of-equations-produce-complex-numbers-2#comment-256522
Wed, 27 Feb 2019 07:03:23 +0000<![CDATA[Also simplifying the answer is fine: Simplify(Solve({(-3sin(a) + y = (-3a + x) cos(a)),(-cos(2a) + y = -2 (-a + x) sin(2a))},{x,y})) Sorry, there's no other improvement we can make with this]]>
https://help.geogebra.org/topic/solving-system-of-equations-produce-complex-numbers-2#comment-256530
Wed, 27 Feb 2019 08:59:29 +0000