VCE Methods Question Thread!

[keltingmeith]

determinant=-9+4k.

just multiply the top column only to perhaps save time and equate it to 3 since 3 is what's on the top right column of the matrix it's meant to be the same as.
27-12k=3
so k=2.
edit: beaten..

Your method is good, but you've found the inverse wrong - should be one over the determinant. Granted, since you have , you can do this:



You still came up with the right answer, however you would've lost a mark for calculating the inverse wrong.

Otherwise, don't be worried about having been beaten to putting up an answer - looking at a different way of doing things is always great, and I certainly encourage you to post a second answer to something I've answered if you answer it in a different way (if any of that made sense )

[alchemy]

Your method is good, but you've found the inverse wrong - should be one over the determinant. Granted, since you have , you can do this:



You still came up with the right answer, however you would've lost a mark for calculating the inverse wrong.

Otherwise, don't be worried about having been beaten to putting up an answer - looking at a different way of doing things is always great, and I certainly encourage you to post a second answer to something I've answered if you answer it in a different way (if any of that made sense )

Oh lol, whoopsies... fixed

[LiquidPaperz]

i still dont understand?

[keltingmeith]

i still dont understand?

That's nice.

What part of which method don't you understand? Where did we lose you?

[LiquidPaperz]

sorry about sounding arrogant. What i dont get is from this attachment onwards howd you get 4k-9 and get rid of the 1/... it.

Could you repeat how do you do the question in the simplest way possible?

Thanks

[keltingmeith]

sorry about sounding arrogant. What i dont get is from this attachment onwards howd you get 4k-9 and get rid of the 1/... it.

Could you repeat how do you do the question in the simplest way possible?

Thanks

Simplest way possible - my method at the very start.

What I did there - multiply both sides by 4k - 9. This means that this now appeared on the left matrix, and cancelled out the fraction on the right matrix. Just some simple transposing of equations, however disguised to be tricky because the denominator was two terms, not just one.

[paper-back]

This may be a silly question but, when do we use the definite integral and when do we use the actual integrated function when applying it to application type questions
E.g.
Let P'(x)= rate of change of population over t time

I find P(x) with given information as;


Now it asks; when does the population exceed 200
Do I do:

Or
 

Thanks

[RKTR]

This may be a silly question but, when do we use the definite integral and when do we use the actual integrated function when applying it to application type questions
E.g.
Let P'(x)= rate of change of population over t time

I find P(x) with given information as;


Now it asks; when does the population exceed 200
Do I do:

Or
 

Thanks

p(x)=200

[paper-back]

Thanks RKTR
But why do we use this instead of the other one?

[paper-back]

 Thanks zezima

[Champ101]

An explanation would be great, thanks!

[Zealous]

Just an integration question, solving for C then subbing in a condition.



Using numerical integration (from Specialist):

[Champ101]

Just an integration question, solving for C then subbing in a condition.

Thanks!

[BLACKCATT]

How do we find the period of two circular functions added together? e.g cos4x+sin2x

[LiquidPaperz]

i and k please, i know how to solve it i.e for i. 2x = 30. but why have they got in solutions 2x = 30, 210, 390, 570, i dont get why they've done 180+x, 270+x etc..? can someone workout both and tell me how they did the steps, please make it simple