Posted by MATHS QUESTION!!!!!!!!!!!!!!!!!!!!!!!!!! on Sunday, December 6, 2009 at 2:00pm.
solve algebriaclly the equation y=2sin2x+1 for 0<_x_<180. when solved find the x coordinates of the roots.
- PLEASE ANSWER MATHS!!! - Reiny, Sunday, December 6, 2009 at 2:18pm
I am assuming you are trying to solve
2sin2x+1 = 0
sin 2x = -1/2
(angle in standard position is 30º)
the sine is negative in quadrants III and IV
so x = 180+30 = 210
or x = 360-x30 = 330
Btw, don't shout!
- Shouting! - Writeacher, Sunday, December 6, 2009 at 2:25pm
When you type in all-caps, two things happen:
**it's harder to read, and
**it's the online equivalent to SHOUTING (considered rude behavior).
Please just type in regular mode, not with the Caps Lock feature turned on. Thanks.
- Correction - Reiny, Sunday, December 6, 2009 at 2:34pm
my last couple of lines should have been
so 2x = 180+30 = 210
or 2x = 360-x30 = 330
so x = 105 or x = 165
since the period of sin 2x is 180º
two other solutions are 285º and 345º
check: 2sin(2x345) + 1 = 0
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