Maths year 11

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    (Original post by 34908seikj)
    Like I said; you'd never get an actual question this messy.
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    You could get a question like this.
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    (Original post by B_9710)
    It should be -7 on the denominator for  \sqrt 7 \times -\sqrt 7 .
    So answer should be  -\frac{1}{18} (5+ 5\sqrt 3 + \sqrt 7 + \sqrt{21} ) I believe.
    -_-

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    (Original post by 34908seikj)
    -_-

    :shot:
    Can you do a few examples on paper please? On these surds about 6 questions from easy to hard.





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    (Original post by z_o_e)
    Can you do a few examples on paper please? On these surds about 6 questions from easy to hard.





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    Sorry I'm not in the house right now so I can't help - I scribbled a few down. I'll be back at around 7-8pm I'm afraid.
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    (Original post by 34908seikj)
    Sorry I'm not in the house right now so I can't help - I scribbled a few down. I'll be back at around 7-8pm I'm afraid.
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    It's fine x I got really sick and had to go doctors :*(

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    How would you solve x^4-12x^2+16=0 ? You are suppose to give answers in the form a+b√c, where a, b, and c are constants?
    Anyone know how to do this?
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    (Original post by Ano9901whichone)
    How would you solve x^4-12x^2+16=0 ? You are suppose to give answers in the form a+b√c, where a, b, and c are constants?
    Anyone know how to do this?
    Thats nasty. Um, looked on wolfram and they managed to the answers. I did the same method as they did, though like I said they got the right answe and I, well, didn't.

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    (Original post by 34908seikj)
    Thats nasty. Um, looked on wolfram and they managed to the answers. I did the same method as they did, though like I said they got the right answe and I, well, didn't.

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    It's not in the correct form. Also  \sqrt{a+\sqrt b} \neq \sqrt a + \sqrt[4] b as your have claimed in the final step of your working.
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    (Original post by B_9710)
    It's not in the correct form. Also  \sqrt{a+\sqrt b} \neq \sqrt a + \sqrt[4] b as your have claimed in the final step of your working.
    Yeah, I don't know how to deal with it; never come across something like that before.

    What should it look like though? For the final step of my working.
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    (Original post by 34908seikj)
    Yeah, I don't know how to deal with it; never come across something like that before.

    What should it look like though? For the final step of my working.
    You've got  x=\pm \sqrt{6\pm 2\sqrt 5 } . You have to get it into the form where there is no square root in a square root.
    Consider the  6+2\sqrt 5 = (a+b\sqrt 5 )^2 .
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    (Original post by 34908seikj)
    Sorry I'm not in the house right now so I can't help - I scribbled a few down. I'll be back at around 7-8pm I'm afraid.
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    Can you explain this please?


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    (Original post by z_o_e)
    Can you explain this please?


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    Root 2275 Simplifiys to 5 root 91

    So now you have 5 root 91 / root 273

    Then rationalise the denominator, so 5 root 91 / root 273 * root 273 / root 273

    This gives you 5 root 24843 / 273

    Root 24843 Simplifiys to 91 root 3

    Now 91 * 5 = 455

    So you have 455 root 3 / 273

    443 cancels with 273 to get 5/3

    This leaves your final answer as 5 root 3 / 3



    Also note 91 can cancel wth 273, however I did it a slightly longer way to keep it straight forward


    Sorry if this is messy or hard to understand I'm literally walking home while I type this
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    (Original post by 34908seikj)
    Root 2275 Simplifiys to 5 root 91

    So now you have 5 root 91 / root 273

    Then rationalise the denominator, so 5 root 91 / root 273 * root 273 / root 273

    This gives you 5 root 24843 / 273

    Root 24843 Simplifiys to 91 root 3

    Now 91 * 5 = 455

    So you have 455 root 3 / 273

    443 cancels with 273 to get 5/3

    This leaves your final answer as 5 root 3 / 3



    Also note 91 can cancel wth 273, however I did it a slightly longer way to keep it straight forward


    Sorry if this is messy or hard to understand I'm literally walking home while I type this
    Thank you so much ♥


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    (Original post by 34908seikj)
    Root 2275 Simplifiys to 5 root 91

    So now you have 5 root 91 / root 273

    Then rationalise the denominator, so 5 root 91 / root 273 * root 273 / root 273

    This gives you 5 root 24843 / 273

    Root 24843 Simplifiys to 91 root 3

    Now 91 * 5 = 455

    So you have 455 root 3 / 273

    443 cancels with 273 to get 5/3

    This leaves your final answer as 5 root 3 / 3



    Also note 91 can cancel wth 273, however I did it a slightly longer way to keep it straight forward


    Sorry if this is messy or hard to understand I'm literally walking home while I type this
    You know when I need to find the final answer I don't know how to find it.



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    (Original post by z_o_e)
    You know when I need to find the final answer I don't know how to find it.



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     (4-\sqrt 7)(6-2\sqrt 7)= 24 +2(7) -8\sqrt 7 -6\sqrt 7 . This can be simplified to  38-14\sqrt 7 . You cannot simplify  14\sqrt 7 , and you add not multiply the  -6\sqrt 7 and  -8\sqrt 7 .
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    (Original post by z_o_e)
    You know when I need to find the final answer I don't know how to find it.



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    For the final answer, only simplify inside the root, once you cannot do that anymore that should be the final answer.


    e,g you cannot simplify the 48 since it's not inside the root, like 7 is. And obviously you can't simplify √7 since it's a prime.
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    (Original post by 34908seikj)
    For the final answer, only simplify inside the root, once you cannot do that anymore that should be the final answer.


    e,g you cannot simplify the 48 since it's not inside the root, like 7 is. And obviously you can't simplify √7 since it's a prime.
    So this is the final answer?

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    (Original post by z_o_e)
    So this is the final answer?

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     38-14\sqrt 7 .
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    (Original post by z_o_e)
    So this is the final answer?

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    Add the 14 and 24 to get 38, now you have 38 - 8 root 7 - 6 root 7

    You can group the minus root 7 together because they're both root 7s
    So (-8-6)root 7 which gives you -14 root 7

    Now you're just left with 38-14 root 7
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    (Original post by 34908seikj)
    Add the 14 and 24 to get 38, now you have 38 - 8 root 7 - 6 root 7

    You can group the minus root 7 together because they're both root 7s
    So (-8-6)root 7 which gives you -14 root 7

    Now you're just left with 38-14 root 7
    What about this?

    Do I find the interior angle and subtract that one by 180?



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