Year 12s: what will be the first way you research your future options? >>

transformation of graphs

Hi Guys,
would you please have a look at the question and the answer below and give your opinion on it. the transformation is clearly is a stretch by a scale factor of 1/2 in x-axis and also translation of (-2, 0) but the answer in mark sheet is saying translation of (-1,0)?????

13461142_2050825655141761_379349528_o.jpg508.1KB

13467523_2050825815141745_1089884968_o.jpg161.4KB

Reply 1

Mowerharvey

For x, if you start the transformation with a stretch, then you must also apply the stretch to the translation.2 * 0.5 = 1, hence the translation of -1.

If you start with the translation first, then you don't need to apply the stretch to the translation.

(edited 7 years ago)

Reply 2

fpmaniac

To avoid this situation, when both transformations are in the x axis, always do translation first then stretch, and when both in y axis, do stretch first then translation

Reply 3

Alen.m

Original post by fpmaniac

To avoid this situation, when both transformations are in the x axis, always do translation first then stretch, and when both in y axis, do stretch first then translation

so for f(x) to be transformed into f(2x+2) , f(x) should be translated by -2 and stretch by the scale factor of 1/2???still the same answer tho

Reply 4

bartbarrow

Original post by Alen.m

so for f(x) to be transformed into f(2x+2) , f(x) should be translated by -2 and stretch by the scale factor of 1/2???still the same answer tho

Yes you have two options:

Stretch sf 1/2 x axis, or f(x) => f(2x)
Translation (-1, 0), or f(2x) => f(2(x+1)) = f(2x+2)

or

Translation (-2), f(x) => f(x+2)
Stretch sf 1/2 x axis, f(x+2) => f(2x+2)