This should have been posted in thePre-Calculussubforum.

Don't plug in 6 forx!! 6 is ayvalue.

Let's compare to . The latter is ahorizontal stretchby a factor of 2. The minimum and maximum y values, if any,do not change. The maximum value of the latter function would still be y = 6.

(Look at a concrete example: and . In both cases, the minimum and maximum values are -1 and 1, respectively.)

Okay, now let's compare to . This time, the latter has avertical shrinkby a factor of 1/3. The minimum and maximum y values, if any,this time, will change. The maximum value of the latter function is nowy = 2(just multiply 6 by 1/3).

(Look at another concrete example: vs. . The min & max values for the original function are -1 and 1, but the min & max values for the transformed function are -1/3 and 1/3.)

Does that help?

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