How do you evaluate the limit #cos((x^5+1)/(x^6+x^5+100))# as x approaches #-oo#?

1 Answer
Aug 30, 2016

The Reqd. Limit#=1#.

Explanation:

The Reqd. Limit #=lim_(xrarr-oo) cos {(x^5+1)/(x^6+x^5+100)}#

#=lim_(xrarr-oo) cos {(x^5(1+1/x^5))/(x^6(1+1/x+100/x^6))}#

#=lim_(xrarr-oo) cos {(1/x)((1+1/x^5)/(1+1/x+100/x^6))}#

Since #cos# is continuous on #RR#, we have,

The Reqd. Limit#=cos {lim_(xrarr-oo) (1/x)((1+1/x^5)/(1+1/x+100/x^6))}#

#=cos {0*((1+0)/(1+0+0))}#.

#=1#.