English

Evaluate the following : limx→∞[(3x2+4)(4x2-6)(5x2+2)4x6+2x4-1] - Mathematics and Statistics

Advertisements
Advertisements

Question

Evaluate the following :

`lim_(x -> ∞) [((3x^2 + 4)(4x^2 - 6)(5x^2 + 2))/(4x^6 + 2x^4 - 1)]`

Sum

Solution

`lim_(x -> ∞) (((3x^2 + 4)(4x^2 - 6)(5x^2 + 2))/x^6)/((4x^6 + 2x^4 - 1)/x^6)`

= `lim_(x -> ∞) (((3x^2 + 4)(4x^2 - 6)(5x^2 + 2))/(x^6))/((4x^6 + 2x^4 - 1)/(x^6))   ...[("Divide numerator and"),("denominator by"  x^6)]`

= `lim_(x -> ∞) (((3x^2 + 4)/x^2)((4x^2 - 6)/x^2)((5x^2 + 2)/x^2))/(4 + 2/x^2 - 1/x^6)`

= `(lim_(x -> ∞) (3 + 4/x^2)(4 - 6/x^2)(5 + 2/x^2))/(lim_(x -> ∞)(4 + 2/x^2 - 1/x^6)`

= `(lim_(x -> ∞) (3 + 4/x^2)*lim_(x -> ∞) 4(4 - 6/x^2)*lim_(x -> ∞) (5 + 2/x^2))/(lim_(x -> ∞)4  + lim_(x -> ∞) 2/x^2 - lim_(x -> ∞)1/x^6)`

= `((3 + 0)(4 - 0)(5 + 0))/(4 + 0 - 0)   ...[lim_(x -> ∞) 1/x^"k" = 0, "k" > 0]`

= `(3 xx 4 xx 5)/4`

= 15

shaalaa.com
Limit at Infinity
  Is there an error in this question or solution?
Chapter 7: Limits - Exercise 7.7 [Page 157]
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×