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    1-sin^2x=sinxcosx
    solve for valuew between 0 and 360
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    cos^2(x) + sin^2(x) = 1
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    yh i simplified that to cos^2x=sinxcosx
    idk what to do next, if i divide by cos^2x i would get tanx=1 but I would lose a solution
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    (Original post by Mathlete18)
    cos^2(x) + sin^2(x) = 1
    yh i simplified that to cos^2x=sinxcosx
    idk what to do next, if i divide by cos^2x i would get tanx=1 but I would lose a solution
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    (Original post by murat10q7)
    yh i simplified that to cos^2x=sinxcosx
    idk what to do next, if i divide by cos^2x i would get tanx=1 but I would lose a solution
    The reason for that is because when dividing by cos^2(x) you are assuming that cos^2(x) is not equal to 0. So you need to also solve for the other case, namely that cos^2(x) does equal 0. Let me know if that helps
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    get everything on the left hand side... then you can factorize out the cosx...
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    (Original post by Mathlete18)
    The reason for that is because when dividing by cos^2(x) you are assuming that cos^2(x) is not equal to 0. So you need to also solve for the other case, namely that cos^2(x) does equal 0. Let me know if that helps
    Thanks I kinda understand but i dont know how to solve it.
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    (Original post by the bear)
    get everything on the left hand side... then you can factorize out the cosx...
    Yh thats what I did but i got cosx(cosx+sinx) =0 idk how cosx=-sinx is gonna help
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    (Original post by murat10q7)
    Yh thats what I did but i got cosx(cosx+sinx) =0 idk how cosx=-sinx is gonna help
    there should be a - in the bracket, not a plus.

    so cosx = 0 or cosx = sinx... now you should be thinking about tanx....
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    (Original post by the bear)
    there should be a - in the bracket, not a plus.

    so cosx = 0 or cosx = sinx... now you should be thinking about tanx....
    thanks i get it now cosx=0 tanx=1
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    (Original post by the bear)
    there should be a - in the bracket, not a plus.

    so cosx = 0 or cosx = sinx... now you should be thinking about tanx....
    I think to solve this you to invade belgium
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    (Original post by murat10q7)
    Yh thats what I did but i got cosx(cosx+sinx) =0 idk how cosx=-sinx is gonna help
    This is basically the same principle as solving for a factorised quadratic:

    If you have a*b = 0 then either a=0 or b=0 or both equal 0.

    In this case a = cosx and b = cosx - sinx

    Therefore the solutions are any solutions to cosx = 0 or cosx - sinx = 0

    This is why if you have (x-a)(x-b)=0 the solutions are x = a and x = b because those are the respective values that makes one of the brackets equal to 0.

    Does that make sense?
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    (Original post by Mathlete18)
    This is basically the same principle as solving for a factorised quadratic:

    If you have a*b = 0 then either a=0 or b=0 or both equal 0.

    In this case a = cosx and b = cosx + sinx

    Therefore the solutions are any solutions to cosx = 0 or cosx + sinx = 0

    This is why if you have (x-a)(x-b)=0 the solutions are x = a and x = b because those are the respective values that makes one of the brackets equal to 0.

    Does that make sense?
    Yep makes perfect sense thanks
 
 
 
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