How do you evaluate the limit of #lim (-x^3+3x^2-4)# as #x->-1#?

2 Answers
Jun 13, 2017

#:. x rarr (-1) lim(-x^3+3x^2-4) =0#

Explanation:

#: x rarr (-0.9999) lim(-x^3+3x^2-4) = -0.0009#

#x rarr (-1^+) lim(-x^3+3x^2-4) = lim(-(-1)^3+3(-1)^2-4) = 0#

#: x rarr (-1.0001) lim(-x^3+3x^2-4) = 0.0009#

#x rarr (-1^-) lim(-x^3+3x^2-4) = lim(-(-1)^3+3(-1)^2-4) = 0#

#:. x rarr (-1) lim(-x^3+3x^2-4) =0# [Ans]

Jun 13, 2017

#0#

Explanation:

#"the limit of a polynomial can be evaluated by substitution"#

#rArrlim_(xto-1)(-x^3+3x^2-4)#

#=-(-1)^3+3(-1)^2-4#

#=0#