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December 22nd, 2018, 06:07 PM  #1 
Newbie Joined: Dec 2018 From: Fife WA Posts: 6 Thanks: 0  Can you help me answer following mathematical questions?
Let f(w) = 2w^3  5. What is f(4)? Let f(w) = 2w^3  5. Let z = 2. What is f(z)? Let g(x) = cos(x/2)  3x. Let f(x) = 2x + 5. What is g(f(x))? Let f(x) = tan(x)  2/x. Let g(x) = x^2 + 8. What is f(x)*g(y)? What is the derivative of x^2  x + 3 at the point x = 5? What is the value of x where x^2  x + 3 is a minimum? In Python, what is returned when evaluating [n for n in range(10) if n % 2]? In Python, what kind of error is returned by the following code? (e.g. NameError, ValueError, IOError, etc.) def my_func(n1, n2): return n1 + n2 my_func(1, 2, 3) What is returned by datetime(1970, 1, 1).strftime('%Y%d%B') in Python? 
December 22nd, 2018, 06:13 PM  #2 
Senior Member Joined: Aug 2012 Posts: 2,259 Thanks: 685  
December 22nd, 2018, 06:40 PM  #3 
Newbie Joined: Dec 2018 From: Fife WA Posts: 6 Thanks: 0  
December 22nd, 2018, 07:40 PM  #4 
Senior Member Joined: Aug 2012 Posts: 2,259 Thanks: 685  
December 22nd, 2018, 07:53 PM  #5  
Newbie Joined: Dec 2018 From: Fife WA Posts: 6 Thanks: 0  Quote:
I used 8 instead of 4. But I was supposed to do 2 x 4x4x4  5 = 123 correct? Last edited by skipjack; December 23rd, 2018 at 08:52 AM.  
December 22nd, 2018, 11:11 PM  #6 
Senior Member Joined: Aug 2012 Posts: 2,259 Thanks: 685  Yes, good. Can you do the second one? This is a pretty mixed bag of questions. Which one(s) are you having trouble with?
Last edited by skipjack; December 23rd, 2018 at 08:52 AM. 
December 22nd, 2018, 11:38 PM  #7 
Newbie Joined: Dec 2018 From: Fife WA Posts: 6 Thanks: 0  
December 23rd, 2018, 05:50 AM  #8 
Math Team Joined: May 2013 From: The Astral plane Posts: 2,138 Thanks: 872 Math Focus: Wibbly wobbly timeywimey stuff.  
December 23rd, 2018, 08:50 AM  #9 
Global Moderator Joined: Dec 2006 Posts: 20,472 Thanks: 2039  The next two questions are done similarly. For z = 2, f(z) = f(2) = 2(2)³  5 = 2(8)  5 = 11. For f(x) = 2x + 5, g(f(x)) = g(2x + 5) = cos((2x + 5)/2)  3(2x + 5), which can be simplified to cos(x + 5/2)  6x  15. In the next question, "*" denotes multiplication. For f(x) = tan(x)  2/x and g(x) = x² + 8, f(x)*g(x) = (tan(x)  2/x)(x² + 8). The next two questions should have been posted in the calculus forum. The derivative of x²  x + 3 is 2x  1. At x = 5, that is 9. Where x²  x + 3 is a minimum, its derivative is zero, so 2x  1 = 0. The required value of x is therefore 1/2. Your remaining questions, relating to Python, should be posted separately in the Computer Science Forum. 

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