Question #999ef

1 Answer
Dec 5, 2017

See below.

Explanation:

First find the inverse of #y=log2x# ( Assuming base 10 )

Rewrite this using the concept of a logarithm:

#10^y=2x=>x=1/2 10^y#

Substituting #y=x#

#y=1/2 10^x#

This is the inverse.

Graph #y=log2x#

x axis intercept when #y=0#

#log2x=0#

Taking antilogarithms:

#2x=10^0=1#

point for graphing #( 1 , 0 )#

as #x->oo# , #color(white)(88)log2x->oo#

as #x->-oo# , #color(white)(88)log2x-># undefined

as #x->0^+# , #color(white)(88)log2x->-oo# ( y axis is vertical asymptote )

as #x->0^-# , #color(white)(88)log2x-># undefined

For #color(white)(888)y=1/2 10^x#

y axis intercept when #x=0#

#y=1/2 10^0=>y=1/2#

x axis intercept when #y=0#

#1/2 10^x=0# ( no solution for real values )

as #x->oo# , #color(white)(888)1/2 10^x->oo#

as #x->-oo# , #color(white)(888)1/2 10^x->0# ( x axis is a horizontal asymptote)

As can be seen from the graph, the inverse is #y=log2x# reflected in the line #y=x#.
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