Cambridge Prelim MX1 Textbook Marathon/Q&A (3 Viewers)

drsabz101

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

the term after n
 

Blitz_N7

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread


What is the best (HSC) method to do part (d)? Thanks in advance.
 

InteGrand

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread


What is the best (HSC) method to do part (d)? Thanks in advance.
Recall that a number is divisible by 3 if and only if the sum of its digits is a multiple of 3. So just find how many ways you can form numbers from that so that the digit sum is a multiple of 3.
 

Blitz_N7

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

Recall that a number is divisible by 3 if and only if the sum of its digits is a multiple of 3. So just find how many ways you can form numbers from that so that the digit sum is a multiple of 3.
Alright, thanks! ^.^
 

appleibeats

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

Screen Shot 2016-06-06 at 8.35.51 pm.png

I found the general formula

Then found T14 and T15

Then made T14/T15 > 1

I then simplified and got sinOcos^9O > 6/15 where O is theta

However I think this is wrong and I don't know where I have gone wrong.

Answers says Theta = 22 degrees
 

Paradoxica

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

View attachment 33248

I found the general formula

Then found T14 and T15

Then made T14/T15 > 1

I then simplified and got sinOcos^9O > 6/15 where O is theta

However I think this is wrong and I don't know where I have gone wrong.

Answers says Theta = 22 degrees
tanθ>2⁄5
θ>tan-12⁄5 ≈ 21.8°
 

Blitz_N7

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

You are right. I misread two as ten. ._.
 

drsabz101

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

Can someone show the working out to these questions:

pic2.PNG - Q5c and d


Extensions question 16 and 17c

17c.PNG

16.PNG
 
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drsabz101

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

why would u let the discriminant equal to 0?
 

integral95

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

why would u let the discriminant equal to 0?
If a quadratic can be factorised in a form of a perfect square,it would only have one root, and letting the discriminant equal to 0 implies there's only one root.
 

drsabz101

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

for q.16 am I supposed to find the discriminant let it equal to 0. What is the next step?
 

InteGrand

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Re: Year 11 Mathematics 3 Unit Cambridge Question & Answer Thread

for q.16 am I supposed to find the discriminant let it equal to 0. What is the next step?
Assume a, b real.











So in summary, the answer is 9.
 

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