Fp1 exam question help

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Similar triangles is widely used as a method for linear-interpolation.

It may be widely used, but i don't think that an A-Level candidates first approach will be to think about similar triangles while attempting this question.

Reply 21

f1mad

Original post by raheem94

It may be widely used, but i don't think that an A-Level candidates first approach will be to think about similar triangles while attempting this question.

That depends on who was taught what. Those who were taught the similar triangles method, definitely would've used it.

Reply 22

Intriguing Alias

Original post by coolstorybrother

question 7 jan 09 fp1 aqa
fp1 jan 09.png

(link if wanted) http://store.aqa.org.uk/qual/gceasa/qp-ms/AQA-MFP1-W-QP-JAN09.PDF

i understand the theory i.e i have to prove it is linear interpolation however i can't seem to obtain the rearranged version for r - mainly the c-d part why is that needed and not just d for the similar triangles?, could someone walk it through please.

Also, on q3 am i right in thinking i have too minus the (pi divided by 2) then divide by -3?
FP1 09 q3.png

I remember this question. My class had a field day :tongue:

Original post by raheem94

And similar triangles is definitely a method used in the AQA textbook and syllabus.

Reply 23

raheem94

Original post by hassi94

I remember this question. My class had a field day :tongue:

And similar triangles is definitely a method used in the AQA textbook and syllabus.

In edexcel text books, this isn't used, nor are the questions in the exams related to it, hence i couldn't figure it out.

Though my method in post#13 was also simple, it would have taken around a minute or two.

Reply 24

coolstorybrother

Original post by TenOfThem

c-d ... yeah I had to think ... but d is already a negative number

Yes you should :frown:

hmm true but im still not sure... could you explain it a bit more? :smile:

EDIT: I think i've got it - you can account for the whole length of that side of the triangle by doing c-d because d is negative? otherwise c+d would only give the difference between the two lengths?
arctan(unless you were trying to say inverse tan 60?) im 100% certain its not in my aqa fp1 spec. why do i need to know it for q3? am i right in thinking you just minus 1/2 and divide by minus 3, once you have the general solution?

(edited 11 years ago)

Reply 25

TenOfThem

Original post by coolstorybrother

EDIT: I think i've got it - you can account for the whole length of that side of the triangle by doing c-d because d is negative? otherwise c+d would only give the difference between the two lengths?

Original post by coolstorybrother

arctan im 100% certain its not in my aqa fp1 spec.