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Simple functions question

  • Thread starter nokia8650
  • Start date
  • #1
219
0
The functions f and g are defined by:

f(x) = x^2 - 2x +3

g(x) = k(x^2) + 1

Given that gf(2) = 16, find the value of k

My solution:

f(2) = 3

g(3) = 9k +1

9k + 1 = 16

k = 15/9

However, the markscheme quotes "16=3k+1" therefore k =5.

I am unable to understand how the markscheme came to this conclusion, please can someonebody help with this. The markscheme may have a mistake, which is what I am thinking!

Thanks
 

Answers and Replies

  • #2
exk
119
0
Your solution looks fine to me. Looks like the key may have made a mistake of not squaring the 3 or something.
 
  • #3
Defennder
Homework Helper
2,591
5
Yeah, it looks like the answer key didn't take into account the square.
 

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