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Showing posts with label Differential Calculus. Show all posts
Showing posts with label Differential Calculus. Show all posts

Sunday, June 22, 2014

Indeterminate Form, Infinity Over Infinity, 2

Category: Differential Calculus, Algebra

"Published in Vacaville, California, USA"

Evaluate


Solution:

To get the value of a given function, let's substitute the value of n to the above equation, we have



Since the answer is -∞/∞, then it is an Indeterminate Form which is not accepted as a final answer in Mathematics. We have to do something first in the given equation so that the final answer will be a real number, rational, or irrational number.

Method 1:

Since the answer is Indeterminate Form, then we have to divide both sides of the fraction by 2n and simplify the given equation as follows



Substitute the value of n to the above equation, we have 



Therefore,


Method 2:

Another method of solving Indeterminate Form is by using L'Hopital's Rule. This is the better method especially if the rational functions cannot be factored. L'Hopitals Rule is applicable if the Indeterminate Form is either 0/0 or ∞/∞. Let's apply the L'Hopital's Rule to the given function by taking the derivative of numerator and denominator with respect to n as follows 




Again, apply the L'Hopital's Rule to the above equation, we have




Since the resulting equation is the same as the given equation, then we cannot use the L'Hopital's Rule because of the repetitive solutions and results. There's no end in this process. In this case, we have to consider the Method 1 in solving the given limits.  


Saturday, June 21, 2014

Indeterminate Form, Zero Over Zero, 5

Category: Differential Calculus, Algebra

"Published in Vacaville, California, USA"

Evaluate:


Solution:

To get the value of a given function, let's substitute the value of x to the above equation, we have


Since the answer is 0/0, then it is an Indeterminate Form which is not accepted as a final answer in Mathematics. We have to do something first in the given equation so that the final answer will be a real number, rational, or irrational number.

Method 1:

Since the answer is Indeterminate Form, then we have to inspect the given function, factor, and then simplify if possible as follows




Substitute the value of x to the above equation, we have



Therefore,


Method 2:

Another method of solving Indeterminate Form is by using L'Hopital's Rule. This is the better method especially if the rational functions cannot be factored. L'Hopitals Rule is applicable if the Indeterminate Form is either 0/0 or ∞/∞. Let's apply the L'Hopital's Rule to the given function by taking the derivative of numerator and denominator with respect to x as follows




Substitute the value of x to the above equation, we have




Therefore,


Friday, March 28, 2014

Finding Equation - Curve

Category: Differential Equations, Integral Calculus, Analytic Geometry, Algebra

"Published in Newark, California, USA"

Find the equation of a curve having the given slope that passes through the indicated point:


Solution:

The slope of a curve is equal to the first derivative of a curve with respect to x. In this case, y' = dy/dx. Let's consider the given slope of a curve



Multiply both sides of the equation by dx, we have
 
 
 

Integrate on both sides of the equation, we have
 
 
 
 
 
   
In order to get the value of arbitrary constant, substitute the value of the given point which is P(5, 4) to the above equation, we have
 
 
 
                                                                                                    
                                                                              
Therefore, the equation of a curve is


Monday, March 3, 2014

Second Derivative Problems - Chain Rule

Category: Differential Calculus, Algebra

"Published in Newark, California, USA"

If y = f(u) and u = Ï•(x), show that 


Solution:

Consider the given two equations above



Since y is a function of u and u is a function of x, then we can apply the derivative of y with respect to x by Chain Rule Method.

Take the derivative of the first equation with respect to u, we have



Take the derivative of the second equation with respect to x, we have



Hence, by Chain Rule Method,



Take the derivative of the above equation with respect to x, we have










but


Hence, the above equation becomes





Therefore,


where