HOW TO: Sketching trigonometric graphs!

[Ken]

i still don't understand your markings for the scale factor

[/0]

graphing becomes a lot harder when they actually set the scale for you :/

[Ken]

oh w8 nvm i actually understand it now, i 4got about the reflection lol thanks a lot dude!

[trinon]

graphing becomes a lot harder when they actually set the scale for you :/

When they set the scale for you they will most of the time set one that accommodates the curve. Regardless, graph a few yourself and once you get the hang of it you'll be able to do it on scales that aren't as familiar.

[tiancaiyimu]

do you think changing the scales would be allowed?
as in, changing the end point x values to the same denominators as your scaling factor?

it's the same but just over the same denominator...

[trinon]

You can change to whatever denominator you want while working out. Do whatever is easiest for you, but when plotting the points on the graph (such as end points or axis intercepts) you should put them in simplified form.

[kurrymuncher]

one question:

lets say I graph the full equation and the x intercepts are just the points where the scale factor is marked. Do I still need to show full working for the x intercepts even if they are clearly shown on the graph?

thanks

[bucket]

not unless it tells you to. most questions just ask you to sketch/plot the graph and don't even leave you room to work out the intercepts =_=

[sxcalexc]

one question:

lets say I graph the full equation and the x intercepts are just the points where the scale factor is marked. Do I still need to show full working for the x intercepts even if they are clearly shown on the graph?

thanks

Hmm trinon said that if it's worth more than one mark we should show working.

[trinon]

one question:

lets say I graph the full equation and the x intercepts are just the points where the scale factor is marked. Do I still need to show full working for the x intercepts even if they are clearly shown on the graph?

thanks

Hmm trinon said that if it's worth more than one mark we should show working.

It varies on each case. Bucket is correct in saying that you should respond to what the question asks. Most of the time in methods, any sort of axis intercept is required. Without it you lose marks. If however the question gives no indication whatsoever of wanting axis intercepts, or goes as far as to say it doesn't want them, then use common sense and don't work them out.

So long as the axis intercepts are there, they don't care for working. The working out is a tool which is used to help find the correct intercepts. If you can do it in your head, then do that. Just be mindful of any question that gives indication that it wants working out.

That being said, no matter how many marks a sketch the graph question is worth, I always include axis intercepts. It doesn't hurt, especially if there is no working out involved.

[trinon]

I've updated the original post to include how to sketch a tan graph.

[bucket]

awesome =]

[xox.happy1.xox]

. I'm just getting the hang of Methods now! Pity it's just before the exam.

[lacoste]

"



"



How did you get the ?
(how did you know which values to pick and how many to pick)?

[TrueTears]

let



so





sin(X) has a period of , so you can add/minus the period from the 1st 2 answers you got, ie 0 and . The rest of the answers are not necessarily needed, you can pick more values if you want, or you can just leave it at 0, and then sub it into the   and then add the period of onto the x values you got.