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    Solve for x, where: -181* < x < 180*

    3cos^2x - 2sinx - 2 = 0
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    um i dont remember much but i'l try
    3cos^2x= 2sinx+2
    3(1-sin^2x)=2sinx+2
    3-3sin^2x=2sinx+2
    0= 3sin^2x + 2sinx-1
    (3sinx-1)(sinx +1)
    sinx=1/3 and sinx=-1
    and find the sin values between the limits from there
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    (Original post by ShireenHeroin)
    um i dont remember much but i'l try
    3cos^2x= 2sinx+2
    3(1-sin^2x)=2sinx+2
    3-3sin^2x=2sinx+2
    0= 3sin^2x + 2sinx-1
    (3sinx-1)(sinx +1)
    sinx=1/3 and sinx=-1
    and find the sin values between the limits from there
    the forum rules say youre not meant to do this...
    youre meant to help someone answer a question, not give them a solution.
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    Right

    Basically you need to get the 3cos^2x in terms of sin x using...

    sin^2x + cos^2x = 1

    Then what i do is then replace all the sin x's with u

    3sin^2x + 2sinx-1 = 0

    so this becomes

    3u^2 + 2u - 1 = 0

    then factorise
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    ther are forum rules
    um sorry....i thought that would help
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    (Original post by ShireenHeroin)
    ther are forum rules
    um sorry....i thought that would help
    Don't worry about it. Reading this could be a good idea though.
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    (Original post by ShireenHeroin)
    ther are forum rules
    um sorry....i thought that would help
    dont worry he didnt exactly ask for help just to have a question solved.

    OP - may i ask why someone is doing C2 work in the middle of the summer though?
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    (Original post by matt^)
    dont worry he didnt exactly ask for help just to have a question solved.

    OP - may i ask why someone is doing C2 work in the middle of the summer though?
    they might want to retake
    doesnt seem so farfetched does it
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    you cant retake until januay. is quite a long way off
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    (Original post by matt^)
    OP - may i ask why someone is doing C2 work in the middle of the summer though?
    I don't think doing some sort of work over the summer, how much or how little it may be, is particularly uncommon (especially for a TSR user :tongue:). People have plenty of reasons. Personally, I'm doing a little work out of interest (well, mostly out of interest - I can't honestly say that FP2 differential equations are that exciting).
 
 
 
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