Thursday, December 15, 2011

x^2+6x-7/x^2+1 greater or equal to 2

We are asked to solve the inequality `(x^2+6x-7)/(x^2+1)>=2`


We can multiply both sides by x^2+1 since it is positive for all x:


`x^2+6x-7>=2(x^2+1)`


`x^2+6x-7>=2x^2+2 `


`x^2-6x+9<=0 `


`(x-3)^2<=0 `


Since the square of a real number is nonnegative, this is true only at x=3.


The solution is x=3.


The graph:


``


Note that the graph approaches y=1 asymptotically"

No comments:

Post a Comment

Thomas Jefferson&#39;s election in 1800 is sometimes called the Revolution of 1800. Why could it be described in this way?

Thomas Jefferson’s election in 1800 can be called the “Revolution of 1800” because it was the first time in America’s short history that pow...