3U Maths Question Thread

[RuiAce]

Hello got 2 questions

1) From a group of 7 men and 5 women, a team of 6 is to be formed
a) How many possible teams are there? I havent done these for ages... is it P or C?
b) What is the probability that the team will have at least 4 men? I know its cases from 4 men, 5 men etc but i forgot how to start off cases since i havent done perms and coms for ages

2) Find the largest possible domain of y= ln(inv sinx) ...

Thank youu )

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You should be able to finish that question from there
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[legorgo18]

2 quick questions:

1) Say for graph y= inv sin(2x -1), for domain do you just go -1< (2x-1) < 1 then solve and plot or am i completely wrong

2) How do i find maximum velocity of v=-4sin (2t+ pi/6)? Do i just differentiate, max tp etc.

[jakesilove]

2 quick questions:

1) Say for graph y= inv sin(2x -1), for domain do you just go -1< (2x-1) < 1 then solve and plot or am i completely wrong

2) How do i find maximum velocity of v=-4sin (2t+ pi/6)? Do i just differentiate, max tp etc.

1) Yep you're absolutely correct!

2) Your velocity is a trigonometric function. Note that for any


the maximum value of y will always be 1 (as it oscillates between -1 and 1). So, the maximum velocity of your graph will occur when the 'sin' bit is equal to negative 1, thus the maximum velocity is 4.

[bsdfjnlkasn]

Hey I wasn't sure of where to put this, but has anyone else had difficulty accessing thsc.com because I need past papers to prepare my assessments but all that keeps coming are error pages
Has it moved to another link? What's the update?

If anyone has any info that would be great

[RuiAce]

Hey I wasn't sure of where to put this, but has anyone else had difficulty accessing thsc.com because I need past papers to prepare my assessments but all that keeps coming are error pages
Has it moved to another link? What's the update?

If anyone has any info that would be great

Website owner is probably doing some management with it if it says "Site offline till June 11"

Pretty annoying tbh. Nothing we can do though; this does happen time and time again

[Wales]

Hey I wasn't sure of where to put this, but has anyone else had difficulty accessing thsc.com because I need past papers to prepare my assessments but all that keeps coming are error pages
Has it moved to another link? What's the update?

If anyone has any info that would be great

Do HSC papers for now if you haven't. Plenty of practice out there

[chelseam]

Hey I wasn't sure of where to put this, but has anyone else had difficulty accessing thsc.com because I need past papers to prepare my assessments but all that keeps coming are error pages
Has it moved to another link? What's the update?

If anyone has any info that would be great

Hey! Here's the 3u page if you needed it https://thsconline.github.io/s/yr12/Maths/assessment-tasks_extension1.html

[pikachu975]

Hey! Here's the 3u page if you needed it https://thsconline.github.io/s/yr12/Maths/assessment-tasks_extension1.html

Can't do papers still

[Wales]

Can't do papers still

I'm getting sharing permission errors. Hopefully it should be fixed soon. Check out HSC papers for now, plenty of them around

[beau77bro]

I think there's a mistake in q9c. Of the first motion test.

[jakesilove]

(Image removed from quote.)

I think there's a mistake in q9c. Of the first motion test.

Yep, good find! Thankfully, the 'final' answer they give is correct, but there's definitely a typo in part of the working out Thanks for letting us know!

[RuiAce]

(Image removed from quote.)

I think there's a mistake in q9c. Of the first motion test.

Action taken. Thank you

[bsdfjnlkasn]

Hey there,

I was wondering if anyone could explain why the final condition v = 2 when t=0 is sufficient to eliminate the negative solution for v? Since t isn't even a variable, what relevance does it have? Is there another way to show that v will be positive in this case? Are there any times when v is negative?

Thank you


EDIT: Is the second solution for determining an expression for the range able to be solved with the following method? (This is how I did it but I got the wrong answer, why is the reasoning incorrect?)

1. Find when vertical velocity = 0 (this time will allow us to deduce the horizontal displacement as the object will be at rest)
2. Sub found time to into x (horizontal displacement)

The answer I got was R = 20sin2(theta)

Thanks again

[jakesilove]

Hey there,

I was wondering if anyone could explain why the final condition v = 2 when t=0 is sufficient to eliminate the negative solution for v? Since t isn't even a variable, what relevance does it have? Is there another way to show that v will be positive in this case? Are there any times when v is negative?

Thank you

Hey! Presumably, when t=0, the particle starts at the origin? If so, sub x=0 into the equation of motion you've derived. You'll find that, at t=0 (ie x=0), velocity could either be +2 or -2. Since you know it starts off as +2, you can eliminate the negative solution!

[yasmineturner]

Hello,

I was wondering if someone could please help me with the question on the photo?

Thankyou