ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: saifh on November 05, 2013, 06:10:01 pm
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How do you solve this question/what are the steps you need to take to solve these?
(http://i.imgur.com/UyBzWML.png)
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How do you solve this question/what are the steps you need to take to solve these?
(http://i.imgur.com/UyBzWML.png)
Well first you have to know the value of what sin(x)=1/2 which is pi/6
Then 2x+pi/3= pi/6 AND pi-pi/6 which 5pi/6 (Because pi is positive in the 2nd Quadrant).
But we want to solve for x, so you have to re-arrange it so that its "x=" and do this for both values that are in the domain given in the Question. :)
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I did that but for some reason got it wrong. Probably algebra issue.
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I get the pi/4, but where does the 13pi/6 come from?:
(http://i.imgur.com/oWByEqx.png)
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I get the pi/4, but where does the 13pi/6 come from?:
(http://i.imgur.com/oWByEqx.png)
Whenever you see a question such as this one, make sure you multiply the domain by the coefficient of x.
So the new domain is 0=<2x=<2pi
Obviously you can approach this using a different method, but I would suggest always changing the domain at the beginning of a question based on the coefficient of x!
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Whenever you see a question such as this one, make sure you multiply the domain by the coefficient of x.
So the new domain is 0=<2x=<2pi
Obviously you can approach this using a different method, but I would suggest always changing the domain at the beginning of a question based on the coefficient of x!
Yeah, what Lucho has explained is why 13pi/6 comes from. :)
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Ah I get it. Seems so simple now.
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Ah I get it. Seems so simple now.
Yup. I forgot to mention that bit about reconstructing the Domain.
Its been a while since I've done a question like that. :P
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Ah I get it. Seems so simple now.
Yeah, always reconstruct the domain first before anything! It sets you up within restrictions that you can't go out of for the whole question, ensuring that you can only make algebraic errors.