4
$\begingroup$

If angles $ (A+B) \in (90°,270°)$ (sum of these two angles lie in the second and third quadrant) and $(A-B) \in (90°,270°)$, can I say $A \in (90°,270°)$ by adding these two, or is it wrong? In the question, I was given this information and had to find which quadrant does angle $A$ belong to. Please justify your answer.

I tried searching on google but then I didn't know how to put my query in words.

$\endgroup$
5
  • $\begingroup$ What do you mean by $(90^\circ, 270^\circ)$? $\endgroup$
    – Jendrik Stelzner
    Commented Jan 2, 2016 at 9:46
  • $\begingroup$ Can you clarify it $\endgroup$
    – Archis Welankar
    Commented Jan 2, 2016 at 9:46
  • $\begingroup$ No if you allow anticlockwise rotations. Consider $A=0$ and $B=100$ $\endgroup$
    – Karl
    Commented Jan 2, 2016 at 10:00
  • $\begingroup$ To clarify there is more than one way to label the quadrants. Hope that helps. $\endgroup$
    – Karl
    Commented Jan 2, 2016 at 10:04
  • $\begingroup$ Sorry I meant clockwise rotations. $\endgroup$
    – Karl
    Commented Jan 2, 2016 at 10:07

1 Answer 1

Reset to default
4
$\begingroup$

Yes, you can do it as you are proposing. The information is only that $90<A+B<270$ and $90<A-B<270$. Adding this inequalities yields the answer.

$\endgroup$
0

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .