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July 13th, 2019, 11:55 PM  #1 
Newbie Joined: Jul 2019 From: Sweden Posts: 2 Thanks: 0 Math Focus: Algebra.  f(f(g)) problem
Hello everybody, I am a noob in this forum. I have a problem combining two functions. f(x) is:  (5cos(pi*x))/(2)  6. g(x) is: (3x/2). For f(g(x)) I have gotten the following result: (15cos(pi*x))/(4)  6, but I donâ€™t know whether that is correct. Can anyone here help? Last edited by skipjack; July 14th, 2019 at 01:21 AM. 
July 14th, 2019, 01:24 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,941 Thanks: 2210 
It's incorrect. f(g(x)) =  (5cos(pi*g(x)))/(2)  6 Now replace g(x) in the righthand side with (3x/2). 
July 14th, 2019, 08:41 PM  #3 
Newbie Joined: Jul 2019 From: Sweden Posts: 2 Thanks: 0 Math Focus: Algebra.  Thanks
Thanks for your kind reply! //Ulf 