Trig equations with ranges that come in the form of pi -- C2

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nisha.sri
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So I was doing some questions in C2 and the question was tanx=5 giving all answers in the domain 0 less than/equal to x less than 2pi.

I'm not quite sure how I would approach this questions
Any help would be appreciated
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gdunne42
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(Original post by nisha.sri)
So I was doing some questions in C2 and the question was tanx=5 giving all answers in the domain 0 less than/equal to x less than 2pi.

I'm not quite sure how I would approach this questions
Any help would be appreciated
Exactly the same as if the angles were given in degrees but you work out and give the solutions in radians.

If sinx=0.5 with your calculator operating in radians x=pi/6 and the second solution would be found by pi-pi/6=5pi/6


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nisha.sri
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(Original post by gdunne42)
Exactly the same as if the angles were given in degrees but you work out and give the solutions in radians.

If sinx=0.5 with your calculator operating in radians x=pi/6 and the second solution would be found by pi-pi/6=5pi/6


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Oh ok we havent covered this at school so that's probably why
So if it was sinx=0.5 what would you type into your calculator ? Just pi/6 but what would that give you ?
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gdunne42
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(Original post by nisha.sri)
Oh ok we havent covered this at school so that's probably why
So if it was sinx=0.5 what would you type into your calculator ? Just pi/6 but what would that give you ?
It doesn't make sense to tackle this question when you don't know anything about radian measure of angles.
If you want to learn more you will find useful tutorials on examsolutions.net
If it was sinx = 0.5 how would you find out what x equals if the problem was in degrees?
You would do the exact same thing if the problem was in radians but how your calculator works in radian measure depends on the calculator.


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BrasenoseAdm
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(Original post by nisha.sri)
So I was doing some questions in C2 and the question was tanx=5 giving all answers in the domain 0 less than/equal to x less than 2pi.

I'm not quite sure how I would approach this questions
Any help would be appreciated
Kudos for reading ahead!

You just need to know how to convert from one to the other.
Degrees to radians eg 45 degrees: divide by 180 and multiply by pi
Radians to degrees eg pi/4: divide by pi and multiply by 180

So with your question, you can solve either in degrees or radians. Either way, take the inverse of each side. If you set the calculator to radians you get the answer directly but you could, if you wanted, obtain the answer in degrees and then convert.

The normal rules (and pitfalls!) apply though. You need to think how many solutions there are over the selected range - there will be the same number for radians as there are for degrees.

After a while, radians become second nature. Some of your questions will require you to make an adjustment to the range and you'll know straightaway (for example) that 450 degrees is 5/2 pi &c!
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