How do you prove that the function #f(x) = (x + 2x^3)^4# is continuous at x=-1? Calculus Limits Definition of Continuity at a Point 1 Answer Bdub Mar 10, 2016 Since #f(-1) = lim x->-1 (f(x))# therefore f(x) is continuous at x = -1 Explanation: #1. f(-1)=(-1+2(-1)^3)^4 =(-1-2)^4=(-3)^4=81# #2. lim x->-1 [(x+2x^3)^4]->(-1+2(-1)^3)^4 =(-1-2)^4=(-3)^4=81# #3.# Since #f(-1)# = #lim x->-1 f(x)# therefore f(x) is continuous at x = -1 Answer link Related questions What are the three conditions for continuity at a point? What is continuity at a point? What is the definition of continuity at a point? What does continuous at a point mean? What makes a function continuous at a point? How do you find the points of continuity and the points of discontinuity for a function? What does continuity mean? How do you use continuity to evaluate the limit #arctan(x^2-4)/(3x^2-6x)#? How do you find the points of continuity of a function? How do you find the continuity of a function on a closed interval? See all questions in Definition of Continuity at a Point Impact of this question 4553 views around the world You can reuse this answer Creative Commons License