Solving the Limit as x Approaches pi/2

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In summary, the limit as x approaches pi/2 is the value that a function approaches as x gets closer and closer to pi/2. To solve this limit, various techniques such as algebraic manipulation, factoring, and finding common denominators can be used. When x approaches pi/2 from the left or right, the limit exists only if the left and right limits are equal. Different functions can have different values for the limit at pi/2. Solving this limit is important because it helps us understand the behavior of a function, determine continuity, and evaluate other complex limits.
  • #1
thenewbosco
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this one looks simpler but i need another one of those tricks i guess:

the limit as x-->pi/2 from the left of:

[tex]\frac{tan x}{ln(cos x)}[/tex]

after taking l'hopital once and simplifying i have ended up with

[tex]\frac{1}{sin x cos x}[/tex]

next is what i don't know
 
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wait never mind i thought of my own trick that works..multiply by 2/2 and use sin2x in the denom.
 
  • #3


To solve this limit, we can use the trigonometric identity: sin x cos x = 1/2 sin 2x. This allows us to rewrite the limit as:

\lim_{x\rightarrow\frac{\pi}{2}} \frac{1}{\frac{1}{2}sin2x}

Now, as x approaches pi/2, sin2x also approaches 1. So, we can rewrite the limit as:

\lim_{x\rightarrow\frac{\pi}{2}} \frac{1}{\frac{1}{2}} = 2

Therefore, the limit as x approaches pi/2 is 2.
 

FAQ: Solving the Limit as x Approaches pi/2

1) What is the definition of a limit as x approaches pi/2?

The limit as x approaches pi/2 is the value that a function approaches as x gets closer and closer to pi/2. It is denoted as lim x→π/2 f(x) and can also be thought of as the y-value of the function at x = pi/2 if it were continuous at that point.

2) How do you solve the limit as x approaches pi/2?

To solve the limit as x approaches pi/2, you can use various techniques such as algebraic manipulation, factoring, and finding common denominators. You may also need to use trigonometric identities or L'Hopital's rule to simplify the expression and evaluate the limit.

3) What happens when x approaches pi/2 from the left and from the right?

When x approaches pi/2 from the left, it means that x is getting closer and closer to pi/2 while still remaining smaller than pi/2. Similarly, when x approaches pi/2 from the right, it means that x is getting closer and closer to pi/2 while remaining larger than pi/2. The limit as x approaches pi/2 exists if and only if the left and right limits are equal.

4) Can the limit as x approaches pi/2 have a different value for different functions?

Yes, the limit as x approaches pi/2 can have a different value for different functions. This is because the behavior of a function near a specific value, such as pi/2, depends on the properties of the function. Some functions may have a finite limit at pi/2, while others may have an infinite limit or may not have a limit at all.

5) Why is it important to solve the limit as x approaches pi/2?

Solving the limit as x approaches pi/2 is important because it helps us understand the behavior of a function near this specific value. It also allows us to determine if a function is continuous at pi/2, which is a crucial concept in calculus. Additionally, the limit at pi/2 can help us evaluate other complex limits involving trigonometric or rational functions.

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