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#1 2009-09-20 19:04:11

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Too tough for a homework assignment?

Hi;

Find all the roots in the closed interval [0°, 360°] without graphing or computer.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#2 2009-09-20 21:02:18

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Too tough for a homework assignment?

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#3 2009-09-20 21:05:38

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: Too tough for a homework assignment?

Hope what I've done is right... it is quite a tough homework assignment, but maybe because of the lengthy algebra

Oh dear Jane got it so quickly tongue

Last edited by Identity (2009-09-20 21:06:24)

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#4 2009-09-21 19:00:06

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Too tough for a homework assignment?

Nice solutions, both:

What grade would you assign this as homework to?


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#5 2009-09-21 21:18:17

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Too tough for a homework assignment?


It’s not difficult. You just need to apply the formula
three times.

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#6 2009-09-21 22:49:11

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: Too tough for a homework assignment?

In Australia we don't learn the double angle formula in high-school (but it is a nice formula)

Although, I guess if you included the formula as a hint (and also possibly ask students to derive it), it would make the problem quite doable.

Although my solution relies on Year 12 Maths, the ending is a bit wishy-washy since it requires you to 'know' that

(which I suspect most people won't have memorized)

Last edited by Identity (2009-09-21 22:51:56)

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#7 2009-09-22 07:36:30

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Too tough for a homework assignment?

Hi all;

Thanks identity for suggesting 12th year,  I think high school math is adequate for it. Jane what grade do you suggest for that question?

Last edited by bobbym (2009-09-22 07:36:48)


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#8 2009-09-22 08:58:28

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Too tough for a homework assignment?

I think this question is suitable for final-year GCSE or first-year A-level students.

Last edited by JaneFairfax (2009-09-27 04:42:34)

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#9 2009-09-22 10:26:35

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Too tough for a homework assignment?

Hi Jane;

Grade? Grade? Stop asking me questions like I knew (or cared) about your American system!
I think this question is suitable for final-year GCSE or first-year A-level students.

I understand, I meant no offense. Thank you for assigning a level of difficulty to it. I understand that system but I am more familiar with my own. I just was asking because I stated to a student that I thought that question was unfair for him.

Last edited by bobbym (2009-09-22 10:29:14)


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Offline

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