Hey ive just started my proper revison of the Higher Maths course, and what not better to begin with the great HSN notes!

While going through the Unit 1 (HSN21000) notes i think ive spotted some mistakes. They are not major mistakes just mistyped no's and signs.

Ok first one is on Page 7, Under "Using simultaneous equations".

The 5th line down, after the addition of the two equations, shouldnt it read,

" 18y=2 ".

Next one is on Page 8, at the very bottom under "Composite Functions".

In example 1b) The 2nd line and after, shouldnt it read,

" f(g(x)) = f(x+1)

=3(x+1)

=3x+3

Can u plz chek these as it mite be me, my maths isnt that great!

Cheers.

**2**

# HSN21000

Started by $impl¥_®i¢h, May 01 2004 08:54 PM

8 replies to this topic

### #1

Posted 01 May 2004 - 08:54 PM

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### #2

Posted 02 May 2004 - 10:44 AM

Yep, I agree with both these mistakes.

### #3

Posted 02 May 2004 - 11:59 AM

Yes, thanks for pointing those out. They'll be fixed shortly

### #4

Posted 05 May 2004 - 03:17 PM

Ok i think ive found another mistake.

This one is on

f(2)=4(2)^3-(2)^2-4(2)+1

= 4(2)-4-8+1

=19

Ok when i do this calculation i get 21 , i think there is a mistake in mulipying out the bracket.

Also on

I would just like 2 know how u have got 2 the 3rd line from the second.

(If all that makes sense Lol)

Thanks

This one is on

**Page18**on**Closed Intervals**, at the bottom right hand corner, where it says,f(2)=4(2)^3-(2)^2-4(2)+1

= 4(2)-4-8+1

=19

Ok when i do this calculation i get 21 , i think there is a mistake in mulipying out the bracket.

Also on

**Page 13**at the bottom example 3, second line, could u plz explain 2 me how 2 carry out that calculation, as i do it differently by spliting the 3 terms and putting them above the "root x", but i get the same answer.I would just like 2 know how u have got 2 the 3rd line from the second.

(If all that makes sense Lol)

Thanks

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### #5

Posted 05 May 2004 - 03:27 PM

Yep, looks like it should be 21. The cube symbol has been missed on the second line. The bit just below will need corrected too.

There is a mistake in the example 3 that you mention, which is probably why you're confused.

Dividing by the square root of x is the same as multiplying by x^(-1/2), not x^(1/2). (However the final answer is still correct).

The brackets can just be multipled out as normal, just like:

a(b + c + d) = ab + ac + ad.

When you have x^a multiplied by x^b their indices just add and it becomes x^(a+B).

Therefore

x^(-1/2) * x^2 = x^(-1/2 + 2) = x^(3/2)

and similarly for the other terms.

Hope this makes sense.

Andy

There is a mistake in the example 3 that you mention, which is probably why you're confused.

Dividing by the square root of x is the same as multiplying by x^(-1/2), not x^(1/2). (However the final answer is still correct).

The brackets can just be multipled out as normal, just like:

a(b + c + d) = ab + ac + ad.

When you have x^a multiplied by x^b their indices just add and it becomes x^(a+B).

Therefore

x^(-1/2) * x^2 = x^(-1/2 + 2) = x^(3/2)

and similarly for the other terms.

Hope this makes sense.

Andy

### #6

Posted 05 May 2004 - 03:36 PM

Yep cheers Andy it does make sense now, i was trying to add the powers as it was multiplication but now see that it was (-1/2) and not (1/2).

Cheers for reply.

Cheers for reply.

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### #7

Posted 05 May 2004 - 04:46 PM

Thanks again, they're on the list

Keep them coming!

Keep them coming!

### #8

Posted 05 May 2004 - 04:49 PM

lol thats me finished Unit 1, so no more mistakes in that (i think).

Ive just started Unit 2 so ill post if i find ne mistakes.

Ive just started Unit 2 so ill post if i find ne mistakes.

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### #9

Posted 05 May 2004 - 07:01 PM

Thanks for pointing those out, they are fixed now and the updated PDFs are available in the Downloads section.

I guess this is the downside of being the first group of people to use these notes!

I guess this is the downside of being the first group of people to use these notes!

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