help
|dw:1513275163598:dw| try to compare what's going on in the function to the table
for example, y = x^2 - 5 looks like y = x^2 - c which means a shift down by c units so what happens to the graph of x^2 to get x^2 - 5?
"f(x) - c is the graph of f(x) shifted down by c units" "x^2 - 5 is the graph of ___ shifted down by __ units" try filling in the blanks
f(x) 5
should be "x^2 shifted down by 5" but you're starting to get the idea ^^
try to apply a similar line of reasoning to y = -2x^2 using row 5 and row 7 of the table
|dw:1513275569852:dw|
using row 5: "the graph of -f(x) is the graph of f(x) reflected across the x-axis" now compare this to what is in the problem y = -x^2 is the graph of ___ reflected across the ___-axis try and fill in the blanks
f(x) x
|dw:1513276001509:dw|
now, use row 7 to figure out how multiplying x^2 by 2 changes the function
umm its reflected?
|dw:1513276199016:dw|
oh okay its stretched
now let's put everything together "the graph of y = -2x^2 is the graph of x^2 stretched vertically by a factor of __ and reflected across the __-axis" try filling in the blanks
y axis and factor of 2?
I think :/
|dw:1513276586156:dw| refer to our earlier statements
f(x) x^2
the factor is 2 the reflection is across x-axis "the graph of y = -2x^2 is the graph of x^2 stretched vertically by a factor of 2 and reflected across the x-axis"
keep in mind your description should mention x^2 not just the generic f(x)
OH I think I understand a little now
now use row 4 to figure out what transformation is being applied to x^2 to get |dw:1513276720205:dw|(x-5)^2
shift to the right?
@Vocaloid
Good but how many units is it being shifted?
5?
Excellent See if you can work out d using the table
Sorry wwas on break, if you do not mind can we still continue ? =)
@563blackghost @Shadow
@Vocaloid
would D be a stretch?
@Vocaloid
well by -3
horizontal or vertical? when you consider stretches and shrinks ignore the negative sign because we account for that with reflection
|dw:1514987990504:dw|
*** should be a shrink since it's inside the parentheses and its > 1
|dw:1514988174150:dw|
now, instead of the generic "a" look at your problem and see what number you would replace "a" with
3
good, now put everything together y = (-3x)^2 is a horizontal shrink by a factor of 1/3 now consider the negative sign
|dw:1514988456667:dw|
\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid good, now put everything together y = (-3x)^2 is a horizontal shrink by a factor of 1/3 now consider the negative sign \(\color{#0cbb34}{\text{End of Quote}}\)
so this would be the answer, or are we not done yet
"now consider the negative sign"
alright
|dw:1514988540829:dw|
add this statement to the answer and then you're done
so reflect f(3)
across the y-axis, yes
reflect f(x) not f(3)
f(3) is a point not a graph
okay so the overall answer would be y = (-3x)^2 is a horizontal shrink by a factor of 1/3. Reflect f(3) over the y-axis.
actually they use y not f(x) so let's write it as "y = (-3x)^2 is a horizontal shrink of y = x^2 by a factor of 1/3 and a reflection of y across the y-axis" done
Reflection of f(3) over the y-axis.**
okay i sort of get it now
you just match up the problem with the table you gave right
yeah, but also think about what is happening to the graph and try to visualize the transformations
okay now lets try a
\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid should be "x^2 shifted down by 5" but you're starting to get the idea ^^ \(\color{#0cbb34}{\text{End of Quote}}\) a is "y shifted down 5 units"
would it be shift f(x) downward c units?
oh okay
that's the correct line in the table but they want you to describe what is happening in the function given in the problem not the generic f(x) and c
5 units are being shifted to the right?
be careful with the parentheses, since the -5 is not inside parentheses it is being applied to the whole function not just x, making it a shift down not right
oh okay
|dw:1514988941034:dw|
so if it would be in the parenthesis it would be right
right and we are on the second one
yeah it would have to be (x-5)^2 to be a shift right
sure
because it is being applied to the entire function
yes
okay so it is being shifted down 5 units?
yes
so the answer would be shifted down 5 units
yes
okay now for b
reflect f(x) in the y-axis?
that's part of it, there's one more transformation though (consider the 2 coefficient)
um shrink f(x) vertically by a factor of a
|dw:1514989351889:dw| for stretches and shrinks you can disregard the negative sign when determining whether a > 1 or < 1
okay so stretch
good, so it stretches it by 2 vertically and reflects across the x-axis = ans
*meant to correct you earlier about the axis of reflection whoops
|dw:1514989455947:dw|
its alright
now for c it would be shift f(x) to the right c units
good, so instead of c it's 5
because everything falls inside the parenthesis
yup
shift f(x) to the right 5 units
good ^^ they use "y" instead of f(x) though so I would just replace f(x) with y
and there is no second transformation for this one right
nope that's it
thank you so much
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