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[naved_s9994]

Heffernan Exam 1 2006 Q4 Solutions. Solving for x

Can anyone verify the exam's solutions'.
Also, how would you type this into CAS, to check (Although this is an Exam 1?)

Solutions to the Question Attached.

Edit: Because it is a VERY simple question, and getting it wrong is very disturbing!

[m@tty]

The solutions are right, and I don't do CAS


Where did you go wrong?

[naved_s9994]

I did it and got x= 2pi/3 and 5pi/6

sin(2x) = -sqrt(3)/2
Hence 2x=-pi/3

and since its negative.....your looking in 3rd and 4th quadrant...

therfore pi+ pi/3
and 2pi-pi/3

and hmm?

[m@tty]

The domain is


Since it is negative you are looking in third and fourth quadrant, but you can't get there anti-clockwise(positive) so you need to go clockwise(negative). Thus you arrive at the solutions;

[naved_s9994]

Thanks a lot! (I got it now), it seems i had forgotten the basics [!?@#$@!~!!]