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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: catherine_mimi on December 08, 2014, 09:20:20 am

Title: Exponential graph
Post by: catherine_mimi on December 08, 2014, 09:20:20 am

Hello~
I need some help determining the rule for a particular exponential graph
The question asks, 'Find the values of a and b such that the graph of y=ae^-bx goes through the points (3,50) and (6,10).
I have figured out that b= 1/3 log_e5 and that a=50e^log_e5, but how does a=250?
Thanks,
Catherine

Title: Re: Exponential graph
Post by: ikiwi on December 08, 2014, 11:01:08 am

e^loge5 = 5 (the e and the loge kind of cancel out)
a = 50 x 5 = 250