Khan/khan-exercises — Issue #11875: Functions 3 - Is -1 squared, or the negation of 1 squared?
Author: KhanBugz
Created: 2012-01-23 00:51:09+00:00
State: open
Labels: lion, safari, wrong-or-unclear

Reporter: tennyson.mccalla@gmail.com

While going through the functions 3 module I happened upon an practice problem that doesn't seem to make sense. The function g(t) says:
g(t)=-t^2-2t-3(f(t))

While the function f(x) says:
f(x)-3x-3

Now it turns out that the t in g(t) is 1. When I started the function's evaluation for 1 I made -t^2 into 1, as -1 multiplied by itself is 1. But the answer to the problem seems to treat it as if it equaled -1!

I could see it being -1, if the problem were formed -(t^2), but that wasn't the way it was written. Because of that step everything else was off and I got a different answer.

Help?

Thanks in advance.

[functions_3.html?seed=130&problem=1](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/functions_3.html?seed=130&problem=1&debug)

[Answer timeline](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/functions_3.html?seed=130&problem=1&debug&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%222%5C%22%22%2C174%5D%2C%5B%22hint-activity%22%2C%220%22%2C3%5D%2C%5B%22hint-activity%22%2C%220%22%2C6%5D%2C%5B%22hint-activity%22%2C%220%22%2C12%5D%2C%5B%22hint-activity%22%2C%220%22%2C33%5D%2C%5B%22hint-activity%22%2C%220%22%2C43%5D%2C%5B%22incorrect-activity%22%2C%22%5C%22-16%5C%22%22%2C80%5D%2C%5B%22hint-activity%22%2C%220%22%2C2%5D%2C%5B%22hint-activity%22%2C%220%22%2C2%5D%2C%5B%22hint-activity%22%2C%220%22%2C4%5D%2C%5B%22hint-activity%22%2C%220%22%2C7%5D%2C%5B%22hint-activity%22%2C%220%22%2C61%5D%2C%5B%22hint-activity%22%2C%220%22%2C63%5D%2C%5B%22correct-activity%22%2C%22%5C%2230%5C%22%22%2C76%5D%5D)

["2","-16","30"]

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