# Help with modulus functions in P2 plz

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#1
Just wanted to know how to deal with modulus functions. For example if x<0 and the funtion is y= /x^2-5/+12 how do u find inverse funtion. Also if u have any good modulus questions please post then here.
0
15 years ago
#2
Just wanted to know how to deal with modulus functions. For example if x<0 and the funtion is y= /x^2-5/+12 how do u find inverse funtion. Also if u have any good modulus questions please post then here.
modulus functions, are just reflected in the x-axis, as there are no negative x values. for the inverse of a function, all yu need to do is swap x for y, and solve for y.
0
15 years ago
#3
With:

y = |x^2-5| +12

You can tell that with |x^2 - 5|, the modulus part is only important when it is negative, or when:

x < √5

So when x > √5, just draw the graph y = x^2 + 8, as the modulus function has no effect past this point - it is making an already positive expression positive.

But when x < √5, the (x^2 - 5) part is reflected about the x-axis, then raised by 12 because of the +12 on the end (I think). x^2 will always be positive for real values of x, but when the binomial (x^2 - 5) goes below zero, the modulus makes it positive, therefore whereas if x = 2,

x^2 - 5:

2^2 - 5 = -1
|2^2 - 5| = 1

So instead of being below the y-axis, it will be the same amount above the y-axis. I think,.
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