How do you find the vertical, horizontal or slant asymptotes for f(x) = (1/x) + 3f(x)=(1x)+3?

1 Answer
Jan 2, 2017

Horizontal: larr y = 3 rarry=3
Vertical : uarr x = 0 darrx=0

Explanation:

graph{x(y-3)(x(y-3)-1)=0x^2 [-20, 20, -10, 10]} y=f(x)=1/x-3y=f(x)=1x3,

Tn the quadratic form,

x(y-3)=1x(y3)=1 .....(1)

As x to 0, y-3 to +-oox0,y3± and this gives y to +-ooy±.

Likewise,

as y-3 to 0, x to +-ooy30,x±

So,

the vertical asy,ptote is x = 0 and

the horizontal asymptote is y = 3.#.

Note

The equation (y-m_1 x-c_1)(y-m_2 x-c_2)=k(ym1xc1)(ym2xc2)=k represents a

hyperbola having the guiding asymptotes

(y-m_1 x-c_1)(y-m_2 x-c_2)=0(ym1xc1)(ym2xc2)=0.

The hyperbola is rectangular, if m_1m_2=-1m1m2=1.

Here, from (1), it is immediate that

x(y-3)=0 gives the pair of perpendicular asymptotes.

See the Socratic graph.

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