The dreaded 10! (1 Viewer)

[jesterofenglish]

Hey,

HSC 2001
10.
b)
ii)

I was going so well until I hit this:

sinx/(1-(sinx)^2) = -3.75

Can some one simplify this for me or tell me if I should never come across this equation.

Trying not to self-combust,

the j.o.e

 

[JayWalker]

Hey,

HSC 2001
10.
b)
ii)

I was going so well until I hit this:

sinx/(1-(sinx)^2) = -3.75

Can some one simplify this for me or tell me if I should never come across this equation.

Trying not to self-combust,

the j.o.e

If (sinx)^2 means sin²x then yes i can help

remember sin²x + cos²x = 1?
Rearrange this and you get cos²x = 1 - sin²x

Therefore you will be left with sinx / cos²x = -3.75

Want me to do rest of question or is that enough?

 

[JayWalker]

I havent actually done this question, but if you really want i can take a look at it.
Otherwise could you post your worked solutions so far? Preferable a scan of your notes or include the use of _TEXT but with the triangle brackets (HTML Tags)

 

[withoutaface]

Hey,

HSC 2001
10.
b)
ii)

I was going so well until I hit this:

sinx/(1-(sinx)^2) = -3.75

Can some one simplify this for me or tell me if I should never come across this equation.

Trying not to self-combust,

the j.o.e

To do this you multiply both sides by 1-sin<Sup>2</sup>x and then use the quadratic formula with respect to sinx.

 

[smallcattle]

Hey,

HSC 2001
10.
b)
ii)

I was going so well until I hit this:

sinx/(1-(sinx)^2) = -3.75

Can some one simplify this for me or tell me if I should never come across this equation.

Trying not to self-combust,

the j.o.e

how did you get sinx/(1-(sinx)^2) = -3.75??

 

[jesterofenglish]

I want!

I havent actually done this question, but if you really want i can take a look at it.
Otherwise could you post your worked solutions so far? Preferable a scan of your notes

I've attached my attempt, mind the hand writing.

Thanx,

This question is driving me insaner!

 

[jesterofenglish]

Too Brilliant

To do this you multiply both sides by 1-sin<Sup>2</sup>x and then use the quadratic formula with respect to sinx.

A stroke of genius! But tried but I got the wrong answer what am I doing wrong?

3.75sin²x-sinx-3.75=0

thus, a=3.75, b=-1, c=-3.75

 

[jesterofenglish]

?

how did you get sinx/(1-(sinx)^2) = -3.75??

What was I suppose to get? Have you done it? What did you get?

 

[monkey187]

A stroke of genius! But tried but I got the wrong answer what am I doing wrong?

3.75sin²x-sinx-3.75=0

thus, a=3.75, b=-1, c=-3.75

your problem is your differentation.

= -250/4cosx

dT/dx = 250sinx/4(cosx)^2
= 250secxtanx/4

 

[Doogsy]

can i just ask what T=t_bus-t_clare means. What is T and why are we finding it?

 

[monkey187]

can i just ask what T=t_bus-t_clare means. What is T and why are we finding it?

Tbus is time taken for bus 2 reach clari T clair is time taken for clair to reach the road

We are trying to find the latest clair can leave home 2 catch the bus

 

[cranberries]

mm,i was doing this question as well but got stuck and then i found out that the distance between the two has to be maximised but why? I was thinking the bus time had to maximised and the running time had to minimised...or something like that

 

[jesterofenglish]

your problem is your differentation.

= -250/4cosx

dT/dx = 250sinx/4(cosx)^2
= 250secxtanx/4

Thanx monkey! I'm such a bonehead! How could I forget the beloved chain rule! But I think it'll still be negative since the derivative of cosx is -sinx (plz correct me if I'm wrong)

cheers everybody

O.Y - (Oh Yeah) Doogsy, we were trying to find out the latest time Claire can leave home and still make the bus for school, personally I think Claire should spare us the trouble and just gig.

 

[monkey187]

haha nah spot on mate

 

[paper cup]

oh I hate this question, but I hate hero and saga more.

 

[Doogsy]

hero and sage is easy as
so was last years, i just cant get the concept with th T=t1-t2, the rest is easy after that too