2 unit, Ext$ension 1 or 2 Mathematics Students Read please! (1 Viewer)

[rokkuran-x]

Can anybody help with this question. It was in my preliminary exam and just couldn't do it

http://i128.photobucket.com/albums/p181/lhiam187/help.jpg

much appreciated :apig:

 

[tommykins]

回复: 2 unit, Ext$ension 1 or 2 Mathematics Students Read please!

Sight, got it right the first time.
ln sqrt[ (2-x)/(2+x) ] = 1/2 ln (2-x)/(2+x) = 1/2ln (2-x) - 1/2ln(2+x) = 1/2 (ln(2-x) - ln(2+x))

Differentiating that, you get -
y' = 1/2[ -1/(2-x) - 1/(2+x)] which simplifies down to = -2/(2-x)(2+x)

 

[SeftonIsAHole]

lnsqrt(2-x/2+x)
=lnsqrt(2-x) - lnsqrt(2+x)
= (1/2)ln(2-x) - (1/2)ln(2+x)
= (1/2)[ln(2-x) - ln(2+x)]
y' = (1/2)[ (-1/2-x) - (1/2+x)]
then simplify and u get ur answer which is
-2/(2-x)(2+x)

yep, the secret to differentiating logarithms is first simplifying it:wave:

 

[chltmddus112]

Our school hasn done that yet =(

 

[Timothy.Siu]

we had a question like that but a bit simpler in our exam, and i didn't split it up i just did it

 

[rokkuran-x]

hmm tommyskins is in year 12
and i've learnt it by myself reading off textbooks, school hasn't taught it yet, pretty much year12 level stuff
so don't be worried, you'll love it next year

well im year 11 and i've done it - i just forgot how to do it in the exam

 

[independantz]

hmm tommyskins is in year 12
and i've learnt it by myself reading off textbooks, school hasn't taught it yet, pretty much year12 level stuff
so don't be worried, you'll love it next year

There's not really much of a distinction between year 12 and year 11 maths as schools can choose to do the topics in any order.

 

[rokkuran-x]

There's not really much of a distinction between year 12 and year 11 maths as schools can choose to do the topics in any order.

we have 2 topics left - geometry and i think its called 'calculus in the real world' or something like that anyway

 

[kaz1]

We haven't started calculus yet.

 

[Aplus]

We haven't started calculus yet.

You've probably covered a lot of the other topics though.

 

[SeftonIsAHole]

We haven't started calculus yet.

wow, calculus is perhaps the one of the most important topics for the HSC as its pretty much a "tool" that you use to do other questions.
Calculus is probably just as important to you know, as learning to add and subtract when you we're in kindergarten.
In saying that, my school (which is partially selective), has only done "introductory calculus".. which is nothing.

 

[Aplus]

Calculas is like 50-60% or more of the course.

 

[Boxes]

Calculas is like 50-60% or more of the course.

aplus my dear child, you are correct.

 

[ratcher0071]

Calculas is like 50-60% or more of the course.

All i know about calculas is differentiation

 

[lyounamu]

All i know about calculas is differentiation

Don't worry, you will be exposed to more calculus in the upcoming years: integration, integration by substitution, definite integral, indefinite integral, Physical Application of calculus, projectile, simple harmonic motion, inverse trig, ah~~~ too much calculus in maths.

 

[Aplus]

Funny how Calculas takes up most of Mathematics when it was only discovered by Newton in the 1600's.