A few days ago
forgivenforsure

Help, trig, f(y)=3-√y?

I don’t understand how this can be a function. For example, they ask me to find for f(4). If that was true, it would be f(4)=3-2 or f(4)=3+2, meaning that f(4) would have two answers, 1 or 5, meaning it would not be a function, correct? For it to be a function, every input must have only one output, right? So how can this be a function? They say the answer is 1. Is there a rule I missed that says you default to the absolute value of the square root?

Thanks.

Top 2 Answers
A few days ago
Maverick

Favorite Answer

Your analysis is correct to a point.

No rule about default value of sqrt being only the positive root, but for the expression to be a true function, you must only look at the positive root of the number – hope this makes sense.

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A few days ago
Crimson Crow
* means square root.

f(y) = 3- *y

f(4) = 3 – *4

f(4) = 3 – 2

f(4) = 1

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