2002 HSC Mathematics 10bii) and iii) (1 Viewer)

[lyounamu]

Does anyone have solution to this? I don't have my Success One books right now so I cannot check whether I got it right.

 

[Timothy.Siu]

i'll check it out

 

[SkimDawg]

ii) A maximum value occurs at x = 0, i.e The brightness increases to a maximum of x = 0 and then decreases

iii)It can be seen that as Nero sails from left to right, the brightness inceases to a maximum at x = -sqrt60 and then decreases to a minimum at x = 0 and again increases to a maximum at x = +-sqrt60 before decreasing again.

Did you want the worked answers? It will take me a while though haha, its very involved.

 

[Timothy.Siu]

ii) A maximum value occurs at x = 0, i.e The brightness increases to a maximum of x = 0 and then decreases

iii)It can be seen that as Nero sails from left to right, the brightness inceases to a maximum at x = -sqrt60 and then decreases to a minimum at x = 0 and again increases to a maximum at x = +-sqrt60 before decreasing again.

Did you want the worked answers? It will take me a while though haha, its very involved.

yup u beat me to it, i got those as well

i just subbed in what they told you b was, and you use their factorization and then find the stat. points and then i just did a table of values to check if it was max/min

 

[ctrlaltv]

For ii) expand everything, sub b=15 in

you will eventually get

dI/dx = [-4x(x^2 + 561)(x^2+17)] / [225+(x+8)^2]^2 * [225+(x-8)^2]^2

dI/dx = 0

you can ignore the dividend since to get 0, the divisor must be 0

you get

-4x(x^2+561)(x^2+17)=0
x=0, sqrt -561, or sqrt -17
sqrt -561, or sqrt -17 are not possible

do the table of values thing, 0 0+e (e = a very small number), 0-e, etc and eventually you will find x = 0 is a maximum

hope i helped =)

 

[lyounamu]

ii) A maximum value occurs at x = 0, i.e The brightness increases to a maximum of x = 0 and then decreases

iii)It can be seen that as Nero sails from left to right, the brightness inceases to a maximum at x = -sqrt60 and then decreases to a minimum at x = 0 and again increases to a maximum at x = +-sqrt60 before decreasing again.

Did you want the worked answers? It will take me a while though haha, its very involved.

Good, very good.

Spot-on. That's what I got. But I wasn't sure because I remember someone getting different answers.

 

[gaaay]

I need help with Question 7 (c) (i)
Chris has four pairs of socks in a drawer, each pair a different colour. He selects socks one at a time and at random from the drawer.

(i) The probability that he does NOT have a matching pair after selecting the second sock is 6/7. Explain why this is o


Hmm. I checked the answers and looked at the tree diagram and i dont understand why the first sock is out of 7 socks. I would expect it to be out of 8 socks.. since there are 8 socks in total? Can someone please explain that to me. thankkkkks

 

[lyounamu]

For ii) expand everything, sub b=15 in

you will eventually get

dI/dx = [-4x(x^2 + 561)(x^2+17)] / [225+(x+8)^2]^2 * [225+(x-8)^2]^2

dI/dx = 0

you can ignore the dividend since to get 0, the divisor must be 0

you get

-4x(x^2+561)(x^2+17)=0
x=0, sqrt -561, or sqrt -17
sqrt -561, or sqrt -17 are not possible

do the table of values thing, 0 0+e (e = a very small number), 0-e, etc and eventually you will find x = 0 is a maximum

hope i helped =)

Thanks for the help. But are you sure about the highlighted part?

I got something like 2x(x^-60)(x^2+260)/@#%^
so x = +_ (plus & minus) SQRT(60) and x=0

and tested the points.

 

[kangms]

I need help with Question 7 (c) (i)
Chris has four pairs of socks in a drawer, each pair a different colour. He selects socks one at a time and at random from the drawer.

(i) The probability that he does NOT have a matching pair after selecting the second sock is 6/7. Explain why this is o


Hmm. I checked the answers and looked at the tree diagram and i dont understand why the first sock is out of 7 socks. I would expect it to be out of 8 socks.. since there are 8 socks in total? Can someone please explain that to me. thankkkkks

The first sock doesn't matter since a chance of drawing any colour is 1. But the second draw, it does matter, since it has to be the same as the first. If the question said a specific colour is to be selected for the first draw, the first one would be out of 8.

 

[lyounamu]

Another Q:

For 2001 HSC Mathematics 10bii), what were your answers?

I am sorry for this. But I would really appreciate some answers that I can compare against.

I only want answers but if you want to post up solution, please do so.

Thanks.

 

[Timothy.Siu]

Another Q:

For 2001 HSC Mathematics 10bii), what were your answers?

I am sorry for this. But I would really appreciate some answers that I can compare against.

I only want answers but if you want to post up solution, please do so.

Thanks.

umm i got sin theta=1/3 so um 86.19 seconds?
btw that was a really good questions!!i liked it