quick questions ... (1 Viewer)

[Lazy Lankan]

hey ... I'm doing maths at uni (first year), and I need some help plz:

1. let's say there is a question where they say something like plot the graph that meets these 'parameters' (wrong word - but I can't think of a betta one):
f(1)=0, f'(2)=5 etc. etc. you get my point ... but then they say it is an odd function! can some1 tell me what happens to a graph of an odd function? An even one is just symmetrical about the y-axis right? but I have no idea about the odd one!

2. if I have a question that says find the limit as x approaches 5 (or some number) and my answer ends up as 1/0 ... does that equate to infinity?!?! coz I got my answer as 1/0 - but the answer said the answer was infinity! maybe I just got the question wrong ... not sure!

 

[FinalFantasy]

for da first one, odd function is symmetrical about da origin

 

[Lazy Lankan]

when u say symmetrical about the origin .... is that the same as symmetrical about y=x ?

 

[Will Hunting]

Nah, man.

An odd function has point symmetry. This means that if some point, (a, b) lies on the graph, then the point, (-a, -b) will also lie on the graph. For example, P(2,8) lies on the graph, y = x^3

Sub x = -2 in y = x^3

y = (-2)^3 = -8

Now, the point (-2,-8) satisfies the equation, therefore the point (-2, -8) also lies on the graph y = x^3

As to your second question, the limit, as x approaches 5, of f(x) being infinity is a viable scenario. This would mean the graph has a vertical asymptote at x = 5. If you want any advances on this, though, you'd better post the actual question you were asked and the other information you're supposed to have about the graph.

 

[Lazy Lankan]

hey thanx ! that was a gr8 explanation ! now I only need help with the 2nd one !

 

[shafqat]

mayb you could post the question itself?

 

[Lazy Lankan]

yeah sorry I wanted to post the question but I was doing random questions - so I have no idea where it is in the textbook! I just want to know whether:

1/0 = infinity ?

 

[velox]

1/0 = undefined.

 

[Lazy Lankan]

oh ok thanx ! stupid question ay ? - lol ... I should have known !