Prelim 2016 Maths Help Thread (1 Viewer)

[kawaiipotato]

there was an answer. Could you please graph it for me David?

tan(pi/2) is undefined since tanx = sinx/cosx and cosx = 0 when x = pi/2.

 

[eyeseeyou]

tan(pi/2) is undefined since tanx = sinx/cosx and cosx = 0 when x = pi/2.

I checked the answer, and you could graph it (I don't know how to insert graphs here)

 

[leehuan]

I checked the answer, and you could graph it (I don't know how to insert graphs here)

What are you graphing again?

 

[eyeseeyou]

So currently I have a mind blank right now. Need help with this question:
Find the inverse function of the following. Also state the domain and range of the inverse function:
Y= (x-2)/(x+2)
Also
sketch on one graph y=f(x)and y=f^(-1) (x):Make sure the diagrams are to scale
1.f(x)=-x^2,x≥0
2.f(x)=tan⁡(π/2),-π≤x≤π

@Leehuan

This was the original question

 

[leehuan]

@Leehuan

This was the original question

Is that supposed to be f(x)=tan(πx/2) ? Or just tan(x/2)?

tan(π/2) itself is undefined

 

[eyeseeyou]

no shit, I wrote the question wrong. It was

f(x)=tan(x/2), -pi blah blah not tan (pi/2)

 

[leehuan]

There's that attitude again. Don't get people to help you only to then use harsh language and curse words later

The graph of y=f(x) i.e. y=tan(x/2) is simply one branch of the tan curve with period 2pi.

On this domain, since f(x) is one-to-one it is indeed invertible. To find the inverse:

Consider x=tan(y/2)
Then arctan(x)=y/2 so y=2 arctan(x)

where arctan is just inverse tan if you have not seen it before. I.e. tan^-1(x)

So we have f^-1(x) = 2arctan(x)

This is a dilated version of the regular inverse tangent curve: the asymptotes are now at pi and -pi, instead of pi/2 and -pi/2

 

[eyeseeyou]

There's that attitude again. Don't get people to help you only to then use harsh language and curse words later

The graph of y=f(x) i.e. y=tan(x/2) is simply one branch of the tan curve with period 2pi.

On this domain, since f(x) is one-to-one it is indeed invertible. To find the inverse:

Consider x=tan(y/2)
Then arctan(x)=y/2 so y=2 arctan(x)

where arctan is just inverse tan if you have not seen it before. I.e. tan^-1(x)

This is a dilated version of the regular inverse tangent curve: the asymptotes are now at pi and -pi, instead of pi/2 and -pi/2
View attachment 33257

When I meant blah blah blah I meant I meant that -pi and when I mean 'blah blah blah" I meant you get the rest of it right?

 

[leehuan]

When I meant blah blah blah I meant I meant that -pi and when I mean 'blah blah blah" I meant you get the rest of it right?

Not the blah blah blah. The unnecessary "no shit" when I just wanted confirmation on a potential correction.

 

[eyeseeyou]

Not the blah blah blah. The unnecessary "no shit" when I just wanted confirmation on a potential correction.

I meant that to myself, I was supposed to be like no...shit...b/c I got it wrong not "no shit". I think I'm rushing into things too quickly

 

[eyeseeyou]

Leehuan, whenever you make mistakes, do you usually say "no...shit" b/c that's what I was trying to say there. I think it's b/c I didn't space it out

 

[leehuan]

Leehuan, whenever you make mistakes, do you usually say "no...shit" b/c that's what I was trying to say there. I think it's b/c I didn't space it out

I would say no shit leehuan (or rather my real name obviously) otherwise it can easily be interpreted wrongly

 

[eyeseeyou]

I would say no shit leehuan (or rather my real name obviously) otherwise it can easily be interpreted wrongly

Do you get why I even said that leehuan?

 

[leehuan]

Well now I do. But clearly earlier on I didn't so make yourself clearer next time. Because I simply felt attacked.

 

[eyeseeyou]

Alright, sorry man

 

[Green Yoda]

No shit was used in wrong context...
Its used more in OTHERS mistakes or obvious mistakes not your mistake...If you made a mistake you cant write 'no shit' its not obvious

Examples when you use 'no shit'
Is the sky blue?
"no shit"

Does earth have gravity?
"no shit"

etc..

 

[eyeseeyou]

No shit was used in wrong context...
Its used more in OTHERS mistakes or obvious mistakes not your mistake...If you made a mistake you cant write 'no shit' its not obvious

Examples when you use 'no shit'
Is the sky blue?
"no shit"

Does earth have gravity?
"no shit"

etc..

I get what you mean but I didn't space it out and used it in the wrong centext. Do you get what I mean rathin?

 

[leehuan]

Even spaced out no shit is usually cursive to the other party.

If you were embarrassed you'd do what I do and actually say no shit at myself

 

[davidgoes4wce]

Can someone please help me with Induction (maths). I really suck at it

1. 1+2+3+...+n=(n(n+1))/2

Here is the solution to the first Induction question

 

[eyeseeyou]

Here is the solution to the first Induction question

Cheers buddy