Showing posts with label Precalculus limits. Show all posts
Showing posts with label Precalculus limits. Show all posts

Monday, February 11, 2013

Precalculus with Limits

Introduction:

In general, the limit is an extension up to which something can go. In mathematics, a limit is an intended height of a function. In other words, a limit is defined as the boundary of a specific area. The function limit is most often used in calculus problems.

Generally it is written as

`lim_(x->c)`  f (x) = K

Where    c - real number (when f(x) is a real valid function).


Properties:

Let the given function be f(x) and x approaches to h.
State all the possibilities.
Simplify the given function to apply the limits and solve.
Replace x for h.
Simplify the function.
The limits of a function could be obtained.

Example problems:

Problem 1: Find the limit of the function f (x) = 3x as x approaches 6.

Solution: Given f (x) = 3x

Substituting the value of x the equation becomes

f (6) = 3 (6) = 18.

So, the limit of f (x) = 3x as x approaches 6 is 18.

Problem 2: Find the limit of the function 9x^2 + 2x – 5 as x approaches 2.

Solution:

Given 9x^2 + 2x – 5

Substituting the values of x

= (9) (2)2 + 2 (2) – 5

= (36 + 4 – 5)

= 35

Hence the limit of 9x^2 + 2x – 5 as x approaches 2 is 35.

Problem 3: Solve (|x^2 - 5x + 6| / (x – 2))  for x approaching to 1

Solution:

Given (|x^2 - 5x + 6| / (x – 2))

Factorize the numerator |x^2 - 5x + 6|

x^2 - 5x + 6 = 0

(x – 2) (x – 3) = 0

The roots are x = 2 and x = 3.

Substitute the roots in the given function

((x – 2) (x – 3) / (x – 2))

Applying the limit

= ((1 - 2) (1 – 3) / (1 – 2))

= (-1) (-2) / (-1)

= 2 / (-1)

= -2

Hence the solution of (|x^2 - 5x + 6| / (x – 2)) is -2

Understanding Derivative Functions is always challenging for me but thanks to all math help websites to help me out.


Practice Problems:

Determine the limit of the function f(y) = -2y as y approaches to 0.5
Answer: -1
Find the limit of f(x) = sin x as x approaches to 0
Answer: 0
Find the limit: f(x) = x^2 - 5x + 6 when x tends to 2
Answer: 0
Solve the following: `lim_(x->3)` (x^2 + 8x + 3) / (x3 + 2x + 1)
Answer: 18 / 17