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# Help with Trig Equations AS watch

1. Hi I need help with this maths question on Trig Equations in a given interval.

The interval is: 0_< x _< 360

_< meaning less than or equal to

and equation: 2Cos(x+55) -0.5 =-0.5

2. (Original post by Vidsify)
Hi I need help with this maths question on Trig Equations in a given interval.

The interval is: 0_< x _< 360

_< meaning less than or equal to

and equation: 2Cos(x+55) -0.5 =-0.5

Have you written the question out correctly? The two -0.5's cancel so you're left with

Post all your working/ideas from here.

Also, using <= is clearer than _<
3. this boils down to (if you re-arrange the interval taking the x+55 (i assume degrees) into acount:

where

solve for phi in the new range, then subtract 55 deg from each solution.
4. (Original post by notnek)
Have you written the question out correctly? The two -0.5's cancel so you're left with

Post all your working/ideas from here.

Also, using <= is clearer than _<
2Cos(x+55)-0.5=-0.5
2Cos(x+55)=0
Cos^-1(0)=90

90
360-90=270

90-55=35
270-55=215
5. (Original post by Vidsify)
2Cos(x+55)-0.5=-0.5
2Cos(x+55)=0
Cos^-1(0)=90

90
360-90=270

90-55=35
270-55=215
Your two solutions are correct. What help did you need? Was it the first step that I gave you in my last post?
6. (Original post by notnek)
Your two solutions are correct. What help did you need? Was it the first step that I gave you in my last post?
Yeah it was the first step that through me as 0/2 isn't possible.
7. (Original post by Vidsify)
Yeah it was the first step that through me as 0/2 isn't possible.
0/2 is possible it is 0

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