Question 743688: I find it confusing. This given graph: http://i40.tinypic.com/lw480.png is stretched vertically by a factor of |1/3| but how would you determine that it is 1/3? I know the 'h' and 'k' values but the 'a' value really is confusing me. I even got a low grade because of it. Can you please explain to me? Any method when it comes to analyzing the 'a' in graphs? Thank you so much!
Answer by josgarithmetic(39617)   (Show Source):
You can put this solution on YOUR website! That graph appears to be vertically compressed, not vertically stretched. The vertex seems to be at the origin, so an equation in standard form would be
 , or simply  . Trying to pick data point values, the factor is in agreement with  . Instead of 1 giving y=1, you have y=~1/3. Instead of 3 giving y=9, you have y=3... x=4 gives ~5 and some small fraction; so .
About the best way to read the factor, a, is to look at the graph and and do a few computations to find the factor. If you have the function but not the graph, then first compute a few points from standard form, and standard position; and then adjust for the factor 'a'.
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