jinny1's Methods Questions Thread :D

[jinny1]

hello. first up.

how do i find x-ints/ y-ints of modulus graphs??

lets say

y= l(x+1)^2-1l - 2

how wud i work out interecepts through working out not by looking at the drawn graph..

thank you

[onur369]

You concentrate on the numbers inside the modulus itself.
In this case it is (x+1)^2 -1
Make it equal to zero (x+1)^2 -1=0
Then find 'x' which in this case equals to 0 and -2. (Make y=0)
To find y, (make x=0)


 

[xZero]

for x-int, let y=0







since ,







for y-int, let x=0







@above, you neglected the -2 outside of the modulus so your answer's wrong

[nacho]

Draw the graph inside the modulus function,
reflect in the x-axis,
shift the reflected graph down 2 units

[jinny1]

Draw the graph inside the modulus function,
reflect in the x-axis,
shift the reflected graph down 2 units

but when you translate the graph down 2 units.. the x and y interceptts change so you wouldnt know where in the axis the final graph will pass through. and thats where xzero's explanation comes in.

IS there any faster way to draw modulus graphs?? or is Nacho + xzero way the fastest?

[pi]

IS there any faster way to draw modulus graphs?? or is Nacho + xzero way the fastest?

It gets faster with practice, its the way I go about it too

[xZero]

IS there any faster way to draw modulus graphs?? or is Nacho + xzero way the fastest?

It gets faster with practice, its the way I go about it too

i agree, practice is the way to go

[jinny1]

new question i really suck at dilation of graphs.

y= -2^x+3 + 1

Dilate this function by a factor of 3 from the x-axis.

I did:

y/3 = -2^x+3 + 1

y= 3(-2^x+3 + 1)

y= 3*-2^x+3 + 3

However the answer is:

y= -3*2^x+3 + 1


what did i do wrong

thanks in advance

[Water]

Rule for Transformation: First to Last

Dilation
Reflection
Translation

So, in any equation, you'll always dilate, then reflection if any, then translate last. With these steps, you should be able to get the right answer.

[nacho]

sibilance

[brightsky]

lol

[jinny1]

lol

u must be laughing at my incompetence

[brightsky]

lol

u must be laughing at my incompetence

woah where did the original post go? ignore that, the post might've been deleted or something..

[jinny1]

I was wondering since i always get these Domain MC questions wrong...

what is the difference between:

R- vs (-inf,0]

R+ vs [0,inf)

[TrueTears]

R^+ means strictly positive reals

R^- means strictly negative reals

thus R^+ is equivalent to (0, infinity)

and R^- is equivalent to (-infinity, 0)

In other words, 0 is not included as it is not positive nor negative.