How do you find the asymptotes for f(x)=(2x)/(sqrt (9x^2-4))f(x)=2x9x24?

1 Answer
Mar 27, 2016

Asymptotes: f(x) = y = +-2/3±23 and x=+-2/3x=±23..

Explanation:

Let y = f(x). It is defined for 9x^2-4>09x24>0. So, |x|>2/3|x|>23.

yto+-ooy± as xto+-2/3x±23. So, x=+-2/3x=±23 are asymptotes..

Inversely, solve for x.
x=(2y)/sqrt(9y^2-4)x=2y9y24.
Interestingly the form is the same. So, |y|>2/3|y|>23.

xto+-oox± as yto+-2/3y±23. So, y=+-2/3y=±23 are asymptotes..

The graph comprises four branches symmetrical about the origin in four regions:

Both x and y > 2/3y>23 in the first quadrant, x<-2/3x<23 and y > 2/3y>23 in the second quadrant, both x and y < -2/3y<23 in the third quadrant and x > 2/3x>23 and y < -2/3y<23 in the fourth quadrant.

As a whole, the graph is outside of |x| <=2/3 and |y|<=2/3|x|23and|y|23.

In this formula, f^(-1)-=ff1f, like f(x) = 1/x. Indeed, interesting.