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    Can someone please explain the answers to part (b) and (ii) of question 6 on the 2015 IAL paper
    https://699d3c34b250207412778630ab10...%20Edexcel.pdf

    My answer to (b) was 150 clockwise? and in (ii) I don't understand how using
    b^2 -4ac shows that det(M) is not equal to zero

    Thank you!
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    Guys, can you do the f(k)=......=5m for an e.g divisible by 5 questions and then rearrange for one term and sub into f(k+1) for *every* divisibility induction question? I think it's my preferred method now. A reply would be much appreciated.
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    (Original post by iMacJack)
    split it up into the sum of r = 1 to 12 of (9r^2-4r) + k lots of the sum of r = 1 to 12 of 2^r

    put r = 1 in to get your a, your n = 12, use the sum of a geometric series formula, youll get a value, add the bits together, equate it to the value given, rearrange for k
    Sorry mate but i dont follow this bit
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    (Original post by connorbarr)
    bruh it says that in the textbook
    I dont have the text book
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    (Original post by OhsoIntrovert)
    Can someone please explain the answers to part (b) and (ii) of question 6 on the 2015 IAL paper
    https://699d3c34b250207412778630ab10...%20Edexcel.pdf

    My answer to (b) was 150 clockwise? and in (ii) I don't understand how using
    b^2 -4ac shows that det(M) is not equal to zero

    Thank you!
    Look in the formula booklet, you'll find a formula involving angles. Which angle would give you this result if you plug it in the formula?
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    (Original post by yesyesyesno)
    Guys, can you do the f(k)=......=5m for an e.g divisible by 5 questions and then rearrange for one term and sub into f(k+1) for *every* divisibility induction question? I think it's my preferred method now. A reply would be much appreciated.
    Yes you can. The method has been used on mark schemes (look a few posts above for an example). My teacher also taught us this method before the f(k+1)-f(k)

    good luck to you tomorrow
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    (Original post by OhsoIntrovert)
    Can someone please explain the answers to part (b) and (ii) of question 6 on the 2015 IAL paper
    https://699d3c34b250207412778630ab10...%20Edexcel.pdf

    My answer to (b) was 150 clockwise? and in (ii) I don't understand how using
    b^2 -4ac shows that det(M) is not equal to zero

    Thank you!
    for the discriminant bit, u get a quadratic when working out the determinant, and then if u out that equal to zero, u only get complex numbers for the roots, but it says that k is a real number so there are no roots where k is a real number meaning no values of k to get a det(M) = 0
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    Guys, can you do the f(k)=......=5m for an e.g divisible by 5 questions and then rearrange for one term and sub into f(k+1) for *every* divisibility induction question? I think it's my preferred method now. A reply would be much appreciated.
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    (Original post by oShahpo)
    Look in the formula booklet, you'll find a formula involving angles. Which angle would give you this result if you plug it in the formula?
    You're quite right. Although I just realised the angle will be a multiple of 45 in FP1 so that question is not part of our spec but good to know

    Thanks for your help
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    (Original post by connorbarr)
    for the discriminant bit, u get a quadratic when working out the determinant, and then if u out that equal to zero, u only get complex numbers for the roots, but it says that k is a real number so there are no roots where k is a real number meaning no values of k to get a det(M) = 0
    and for that rotation thing, I swear we only have to do multiples of 45 degrees
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    (Original post by OhsoIntrovert)
    Yes you can. The method has been used on mark schemes (look a few posts above for an example). My teacher also taught us this method before the f(k+1)-f(k)

    good luck to you tomorrow
    Thank you! Goodluck to you too if you're sitting it
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    (Original post by connorbarr)
    for the discriminant bit, u get a quadratic when working out the determinant, and then if u out that equal to zero, u only get complex numbers for the roots, but it says that k is a real number so there are no roots where k is a real number meaning no values of k to get a det(M) = 0
    Thanks! This makes sense now and was well explained
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    (Original post by kingaaran)
    Sorry took awhile. Two methods. I'd prefer the second, but most would go for the first

    Attachment 534849Attachment 534851


    Posted from TSR Mobile
    Thank you SO MUCH!!!
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    (Original post by yesyesyesno)
    Guys, can you do the f(k)=......=5m for an e.g divisible by 5 questions and then rearrange for one term and sub into f(k+1) for *every* divisibility induction question? I think it's my preferred method now. A reply would be much appreciated.
    Hey mate
    Could you do me a favour and explain how your method would work for this?

    https://gyazo.com/ef16da65fc0475a8ce387015bbd6bb08

    Thanks!!!
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    (Original post by iMacJack)
    Split it up into the sum of r = 1 to 12 of (9r^2-4r) + k lots of the sum of r = 1 to 12 of 2^r

    put r = 1 in to get your a, your n = 12, use the sum of a geometric series formula, youll get a value, add the bits together, equate it to the value given, rearrange for k
    was k = 2/15?
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    (Original post by tazza ma razza)
    was k = 2/15?
    Yes
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    (Original post by alfmeister)
    No I haven't as Im on my phone now so don't have the link

    Posted from TSR Mobile
    This is the link for it please http://crashmaths.com/wp-content/upl...-Worksheet.pdf question 14b, thanks so much
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    (Original post by OhsoIntrovert)
    You're quite right. Although I just realised the angle will be a multiple of 45 in FP1 so that question is not part of our spec but good to know

    Thanks for your help
    Glad to have helped
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    Well just did June 2014 and got 72/75 (lost 3 marks because I got my negative signs mixed up ) so that has boosted my confidence
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    (Original post by economicss)
    This is the link for it please http://crashmaths.com/wp-content/upl...-Worksheet.pdf question 14b, thanks so much
    What have you done so far? Do you have equations of the tangents to both points P and Q. You then need to equate the equations of the tangents.

    Posted from TSR Mobile
 
 
 
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