Find the limit... ? Calculus Limits Formal Definition of a Limit at a Point 2 Answers Steve M Jan 13, 2017 See Above Answer link Cesareo R. Jan 13, 2017 #1/2# Explanation: #sqrt(9x^2+3x)-3x=(9x^2+3x-9x^2)/(sqrt(9x^2+3x)+3x)= (3x)/(sqrt(9x^2+3x)+3x)# but #(3x)/(sqrt(9x^2+3x)+3x)=(3x)/(3x(sqrt(1+1/(3x))+1))=1/(sqrt(1+1/(3x))+1)# finally #lim_(x->oo)sqrt(9x^2+3x)-3x=lim_(x->oo)1/(sqrt(1+1/(3x))+1)=1/2# Answer link Related questions How do you use the epsilon delta definition of limit to prove that #lim_(x->5)(x-1)= 4# ? How do you use the epsilon delta definition of limit to prove that #lim_(x->1)(x+2)= 3# ? What is the formal definition of limit? How do you use the limit definition to prove a limit exists? What is the definition of limit in calculus? How do you find the limit using the epsilon delta definition? How do you use the epsilon delta definition to prove a limit exists? What is the epsilon delta definition of limit? How do you find values of δ that correspond to ε=0.1, ε=0.05, and ε=.01 when finding the limit... How do you prove that the limit of #3x+5=35# as x approaches 10 using the precise definition of a limit? See all questions in Formal Definition of a Limit at a Point Impact of this question 1695 views around the world You can reuse this answer Creative Commons License