Y = -3 f(x+2) - 7 (Function help)

  • Thread starter firstwave
  • Start date
In summary, the conversation is about a person asking for help with understanding function notation in order to complete an assignment due the next day. The expert explains that the function definition tells you how to transform the argument passed into the function, and provides an example to illustrate this concept. The person then expresses gratitude for the explanation and states that they now understand all five functions they needed help with.
  • #1
firstwave
12
0
Hey I am left with this question and I have no clue how to do it

y = -3 f(x+2) - 7 (Function help!)

1. f(x) = x
2. f(x) = x^2
3. f(x) = |x|
4. f(x) = 1/x
5. f(x) = (square root of 2) how do i write that out?

Basically I am suppose to substitute the 5 things into the equation and the graph it. I am confident that I can graph it with no problems. However, I can't do the first part, which is to put the 5 f(x) things into the equation

Help please, its due tomorrow:(
I'll check for replies frequently so if u can help me..GREAT!

Thx in advance guys
 
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  • #2
No problem! :smile:

If you're unsure about function notation, all you need to know is this: the definition of the function tells you what to do to (how to "transform" or change) the argument (ie the variable) that you are passing into the function. So let's take an example:

If you have a function defined by:

f(x) = x2

then, when you pass the argument 'x' into the function, whatever value it has is squared. Now, what if we evaluate the function for a more complicated argument?

If f(x) = x2, then what is:

f(x+2) ?

Same rule! The function definition is a general statement that whatever argument is passed into the function is squared, not matter what it is.

So f(x+2) = (x+2)2

If you still can't see it, notice that we're just evaluating the function for a different variable, which we could define by u = x + 2. Obviously by definition:

f(u) = u2 = (x+2)2

Well, that example just happens to take care of your # 2. Can you do the rest?
 
  • #3
yes thanks so much I think I understand all 5 now

THX!
 

1. What is the function of Y = -3 f(x+2) - 7?

The function Y = -3 f(x+2) - 7 represents a transformation of the original function f(x). The -3 in front of f(x+2) indicates a vertical stretch or compression, while the +2 inside the parentheses indicates a horizontal shift. The -7 at the end indicates a vertical shift.

2. How do I graph Y = -3 f(x+2) - 7?

To graph this function, first graph the original function f(x). Then, apply the transformation by either vertically stretching or compressing the graph, shifting it horizontally, and then shifting it vertically. The resulting graph will be the graph of Y = -3 f(x+2) - 7.

3. What is the role of the -3 in the function Y = -3 f(x+2) - 7?

The -3 in the function Y = -3 f(x+2) - 7 acts as a vertical stretch or compression factor. If the absolute value of -3 is less than 1, it will compress the graph vertically. If it is greater than 1, it will stretch the graph vertically.

4. How do I determine the horizontal shift in Y = -3 f(x+2) - 7?

The value inside the parentheses, in this case +2, indicates the horizontal shift. A positive value indicates a shift to the left, while a negative value indicates a shift to the right.

5. What is the effect of the -7 at the end of the function Y = -3 f(x+2) - 7?

The -7 at the end of the function Y = -3 f(x+2) - 7 acts as a vertical shift. A positive value will shift the graph upwards, while a negative value will shift the graph downwards.

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