English

Evaluate the following limit: limx→-2[x7+x5+160x3+8] - Mathematics and Statistics

Advertisements
Advertisements

Question

Evaluate the following limit:

`lim_(x -> - 2)[(x^7 + x^5 + 160)/(x^3 + 8)]`

Sum

Solution

`lim_(x -> - 2)[(x^7 + x^5 + 160)/(x^3 + 8)]`

= `lim_(x -> - 2) ((x^7 + 128) + (x^5 + 32))/(x^3 + 8)`

= `lim_(x-> - 2) (((x^7 + 128) + (x^5 + 32))/(x + 2))/((x^3 + 8)/(x + 2))      ...[("As"  x -> - 2","  x ≠ -2),(therefore x + 2 ≠ 0),("Divide Numerator and"),("Denominator by"  x + 2)]`

= `(lim_(x -> - 2) ((x^7 + 2^7)/(x + 2) + (x^5 + 2^5)/(x + 2)))/(lim_(x -> - 2)((x^3 + 2^3)/(x + 2))`

= `(lim_(x -> - 2) (x^7 - ( - 2)^7)/(x - ( - 2)) + lim_(x -> - 2) (x^5 - ( - 2)^5)/(x - ( - 2)))/(lim_(x -> - 2) (x^3 - ( - 2)^3)/(x - ( - 2))`

= `(7 (-2)^6 + 5(-2)^4)/(3 (-2)^2)     ...[lim_(x -> "a") (x^"n" - "a"^"n")/(x - "a") = "na"^("n" - 1)]`

= `(7(64) + 5(16))/(3(4)`

= `(448 + 80)/12`

= `528/12`

= 44

shaalaa.com
Factorization Method
  Is there an error in this question or solution?
Chapter 7: Limits - EXERCISE 7.2 [Page 102]
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×