Carelessness in maths

last SG · 2011-11-04T06:06:57+00:00

I tend to be quite careless too. Like mistyping an extra digit or omitting certain calculator values by pressing the keys too quickly..What i have been doing...

wee_ws SG

Hi donkhead333,

"from 100" - We take 100 as the reference value.

"within 60" - Add 60 to the reference value gives us the upper limit 160. Take away 60 from the reference value gives us the lower limit 40.

Thus we obtain a range of values between 40 and 160.

In N08/P2/Q1(iv), we encounter a similar type of phrasing:

...for which the value of g(x) is within +/-0.5 of the value of f(x).

It is thus important to know how to interpret this information correctly :)

Thanks.

Cheers,
Wen Shih

qdtimes2 SG

finish paper in 2 hrs, use 1hr check :S :S :S ...if u can...

wee_ws SG

Hi,

Here is a list of common mistakes to avoid, nicely organised in a single document for all students to reflect upon on their last-lap towards the exam next week:

http://wenshih.files.wordpress.com/2010/02/common-mistakes-to-avoid.pdf

It is also beneficial for students to look back at past problems they have solved and ensure that familiarity with a variety of problem-solving approaches have been firmly established. Past problems from these sources will be most relevant:

1. JC 1 MYE 2010,

2. JC 1 Promo 2010,

3. JC 2 MYE 2011,

4. JC 2 Prelim 2011,

5. Nov 2010 H2 Maths Exam,

6. Nov 2009 H2 Maths Exam,

7. Nov 2008 H2 Maths Exam,

8. Two other schools' prelim 2011 papers you have done.

Jiayou!

Cheers,
Wen Shih

eagle SG

Hi,

Here is a list of common mistakes to avoid, nicely organised in a single document for all students to reflect upon on their last-lap towards the exam next week:

http://wenshih.files.wordpress.com/2010/02/common-mistakes-to-avoid.pdf

1. JC 1 MYE 2010,

2. JC 1 Promo 2010,

3. JC 2 MYE 2011,

4. JC 2 Prelim 2011,

5. Nov 2010 H2 Maths Exam,

6. Nov 2009 H2 Maths Exam,

7. Nov 2008 H2 Maths Exam,

8. Two other schools' prelim 2011 papers you have done.

Jiayou!

Cheers,
Wen Shih

Thanks for sharing

http://wenshih.files.wordpress.com/2010/02/common-mistakes-to-avoid.pdf

This is extremely useful stuff.

wee_ws SG

Hi,

Thanks eagle for your encouragement :)

I made this mistake in this question about transformation on one occasion. Given the graph of y = f(2x), one is asked to sketch the graph of y = f(2x - 4). I simply took it as a translation of 4 units to the right when it should have been a translation of 2 units to the right.

Thus one should ask what substitution should x be made to decide on the correction transformation. In the example, x is substituted with x - 2 to obtain f(2x - 4) from f(2x).

Thanks.

Cheers,
Wen Shih

eagle SG

Hi,

Thanks eagle for your encouragement :)

Thus one should ask what substitution should x be made to decide on the correction transformation. In the example, x is substituted with x - 2 to obtain f(2x - 4) from f(2x).

Thanks.

Cheers,
Wen Shih

That's right.

I have a method which reduces the careless mistakes and improves understanding on these type of questions. It also helps students to easily understand how to transform from f(x) t0 f(-|x|).

This method is also applicable to transformations in conics, and good to link between conics transformation and normal curves transformation.

Will find some time to put my ideas into words on paper and pass it to you.

Thanks ;)

wee_ws SG

Dear eagle,

Thanks in advance!

Cheers,
Wen Shih

wee_ws SG

Hi,

Here is another example of a mistake.

A student wishes to find least n from the following inequality:

P(-sqrt(n)/2 < Z < sqrt(n)/2) > 0.95.

She uses GC to find the inverse Normal of 0.95.

Thanks.

Cheers,
Wen Shih

« Previous Page