VCE Methods Question Thread!

[qazser]

How would u do 14,15,18?

Thanks in advance,
qazser

[byCrypt]

How would u do 14,15,18?

Thanks in advance,
qazser

For question 15, I think you could use the quadratic formula to solve for the solutions. You should end up with an expression in terms of k. Under the radical, you should have k^2+k+1. And you can argue that since this is always positive for all values of k, the solution are all defined.

k=-1 is the only exception. When k=-1, the original equation becomes linear, but there is still a solution as -2x+1=0 can be solved to give x=1/2.

Hence, the equation has a solution for all values of k.

I hope this helps!

[qazser]

For question 15, I think you could use the quadratic formula to solve for the solutions. You should end up with an expression in terms of k. Under the radical, you should have k^2+k+1. And you can argue that since this is always positive for all values of k, the solution are all defined.

k=-1 is the only exception. When k=-1, the original equation becomes linear, but there is still a solution as -2x+1=0 can be solved to give x=1/2.

Hence, the equation has a solution for all values of k.

I hope this helps!

Ty, will look into it

btw, whats rational root theorem? The textbook has alpha and beta symbols that dont make any sense

[keltingmeith]

Ty, will look into it

btw, whats rational root theorem? The textbook has alpha and beta symbols that dont make any sense

Hmmm, send through a picture? We might be able to help you make sense of it. (I know a few theorems that might be called the "rational root theorem", so)

[qazser]

Hmmm, send through a picture? We might be able to help you make sense of it. (I know a few theorems that might be called the "rational root theorem", so)

Pics attached below Ty Euler again

[keltingmeith]

Awkward moment when I have never seen this before. Awks.

Okay, I think what it's saying is to check the leading and constant terms of the expression (eg, if you have ax^3+bx^2+cx+d, check a and d), and make sure that the only factor they share is 1. (remember: factors are the list of numbers that the number is divisible by. For 10, this is 10, 5, 2 and 1. For 11, it's just 11 and 1. For 6, it's 6, 3, 2 and 1) If this holds true, proceed to the next step. If this does not hold true... You can probably try this anyway.

Next, guess that the linear factor might take the form a*x+d*, where a* is one of the factors of a, and d* is one of the factors of d. Then, just try all of those solutions in the factor theorem to see if any of those are a factor. I think the rational root theorem says that one of them must be? But I could be wrong, as I said, never seen this before, and the book does a pretty poor job of explaining it.

[StupidProdigy]

Pics attached below Ty Euler again

It's mentioned in this thread. Specialist Question Thread!
Video example https://www.youtube.com/watch?v=GTx-rXTQg1o
So yeah as Euler said and using his example, you need to find the integer factors of 'a' and the integer factors of 'd'. Once you have found these then you make all possible combinations of the factors you found, the combinations must be in the form: (factors of d)/(factors of a). Then sub these in to your function until one gives f(x)=0 and then you have a rational root

[qazser]

It's mentioned in this thread. Specialist Question Thread!
Video example https://www.youtube.com/watch?v=GTx-rXTQg1o
So yeah as Euler said and using his example, you need to find the integer factors of 'a' and the integer factors of 'd'. Once you have found these then you make all possible combinations of the factors you found, the combinations must be in the form: (factors of d)/(factors of a). Then sub these in to your function until one gives f(x)=0 and then you have a rational root

Ty Prodigy and Euler

[upandgo]

hi guys! for extended response questions, if you didn't get the EXACT answer but got a value very close to it would you still receive full marks?

for example, if a question asked me 'how many hours would it take to empty a litre of water' and the actual answer is 16 hours 40 mins but my answer is 17 hours? thanks in advance! 

[Biology24123]

hi guys! for extended response questions, if you didn't get the EXACT answer but got a value very close to it would you still receive full marks?

for example, if a question asked me 'how many hours would it take to empty a litre of water' and the actual answer is 16 hours 40 mins but my answer is 17 hours? thanks in advance! 

The question would usually say something like to the closest hour or closest 10 minutes. Sig figs as well are important

[upandgo]

The question would usually say something like to the closest hour or closest 10 minutes. Sig figs as well are important

thanks for your help 

[Maz]

hey, can someone help me with this ...its the first question...
for the first part i thought you just count the little squares inside the graph and divide it by the total number of little squares...either thats wrong or my ability to count little squares is terrible haha ...and i don't know how to do the second the third part to it (over and underestimating)...so i was wandering if i could please get some help?
id appreciate it a lot 

[qazser]

hey, can someone help me with this ...its the first question...
for the first part i thought you just count the little squares inside the graph and divide it by the total number of little squares...either thats wrong or my ability to count little squares is terrible haha ...and i don't know how to do the second the third part to it (over and underestimating)...so i was wandering if i could please get some help?
id appreciate it a lot 

Use integration, counting squares is not very accurate and i wouldn't rely on that

19 squares? Can't count either

[Maz]

Use integration, counting squares is not very accurate and i wouldn't rely on that

19 squares? Can't count either

how would you use integration?

[qazser]

how would you use integration?

https://www.youtube.com/watch?v=1FICxdXswIs

Here's a quick vid i found