Determine all the values of angle if and is between and . Give the answers correct to 1 decimal place.

This is weird, I have solved to the point that and is in . Hence one of the options should have only 2 answers. Did I go wrong?

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- February 5th 2010, 06:32 AMPunchWeird MCQ options!
Determine all the values of angle if and is between and . Give the answers correct to 1 decimal place.

This is weird, I have solved to the point that and is in . Hence one of the options should have only 2 answers. Did I go wrong? - February 5th 2010, 06:47 AMe^(i*pi)
You didn't go wrong but rather didn't complete the whole equation. The problem you made appears to be that you cancelled out sin(x) which you can't do because sin(x) is potentially 0. I've outlined the method using factorising below

From the domain restrictions

Multiply by cos(x) and factorise

or

This is because cos(x) is symmetrical in the line so we can do where 180-70.5 is the distance the first point is away from 180 - February 5th 2010, 06:55 AMPunch
- February 5th 2010, 07:08 AMe^(i*pi)
Nope. Attached is the graph of this question, on it you can see that 0 and 180 are definitely crossing points.

If you'd cancelled sin(x) you'd have been dividing by 0 at the points 0, 180 and 360.

In general it's always better to look for a factorising solution first - February 5th 2010, 09:54 PMPunch
I will move everything to the left side or right side before factorizing the common items and equating them to values before solving... thanks!