Try These Funky Limits! lim (3x 1. 2 x →0 8 + x3 lim 2 x→ −2 x + 2 x x4 −1 lim 3 x →1 1 − x 5. lim9 − 5( x − 2) x 2 − 6x + 7 8. lim 2 x →1 x − 8 x + 9 4. 7. − 2 x − 7) x2 − 5 2. lim x →1 2 − x x →2 10. 13. x3 − 8 lim 2 x → 2 x − 9 x + 14 x+6−3 x−3 lim x →3 16. 19. 11. x 2 − 12 x + 36 14. lim 2 x − 12 x →6 17. lim 20. lim x→4 x−4 x−4 lim 5 x 23. lim x →1 33. lim x →2 lim 29. x − 3x − 2 5 − x − 2x 1 − 7 − 3x 2x + 5 − x + 7 2 2 x − 2 −2 x 35. lim 3 x − 2 −3 x x →0 2 1 − 4x x − 2x 1 x−2 2 x 3 − 5x 2 + 3 x − 2 lim 2x − 4 x →2 x 3 − 2 x 2 + 23 26. lim 23 x 4 − 7 x → x→ − 31. 1 4 x→2+ 42 x 3 − 2 x + 5 25. lim 6x3 − 7 x → 28. lim x→ x →0 22. 6. 2 x − 2−x lim x −x x→0 2 + 2 x 3 − 2x − 5 9. lim 2x3 − 7 x→2 12. 32. 3x lim x x→+ 4 lim x →0 x +1 − 2x +1 3x + 4 − 2 x + 4 1 1 − 34. lim 3 + x 3 x x →0 1 x3 − 2 36. lim x −8 x →8 x−4 lim 2 − x→4 h →0 ( x + a) 2 lim 2 2 x→a x + a 2x 18 x − h lim h − 6 x x2 − 1 3. lim x → −1 1 + x x 81 − x 4 15. lim x→ − 3 x + 3 −1 18. lim x 21. lim 2 x 24. lim x →0− 3 1 x →0− −1 x→ − 5x 27. 2 − x8 lim 7 x → 3 x − 11 30. 5x lim x x → 4 Limits Help Sheet Methods for finding limits: • Using your brain - if the limit is obvious by looking at it, then just write the answer! • Substitution - if you can substitute the value into the expression without encountering an indeterminate form like 0 0 or then go ahead and do it. Don’t waste time with the other methods! • Factor - if you do have an indeterminate form, factor first, then divide out the troublesome term. Note: you may have to factor expressions that aren’t as pretty as previous grades (like square roots etc..) • Divide top & bottom by highest power of x - this only works if you are approaching + or − (Use your horizontal asymptote strategies from Advanced Functions for this) • Rationalize numerator, denominator or both - always choose the easier one first! • Ingenuity - sometimes the best solution is to go with a gut feeling. Don’t be afraid to try something new! Reminders: • Make sure you know why you are doing something. If you don’t know, why bother? • If you wish to verify your answer, you can try a value on your calculator, but this is only a guess/check! • Most of the time, the algebraic limit is the same from the left and from the right, BUT NOT ALWAYS! If you have an asymptote, a discontinuity (in the graph), or a domain restriction (like a square root or a log), make sure you check both limits! 0 something = 0 and • Remember that = DNE ( + or − ). Don’t make life difficult! something 0 • If you can, picture the graph to help you figure out a limit.