Limit lim(x->pi/4) tan(2x) =tan(pi/2)

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In summary, the limit of tan(2x) as x approaches pi/2 is undefined. This can be seen by looking at the graph of tan(x) and seeing that the function approaches positive and negative infinity from the left and right of pi/2. The limit does not exist because the limit from the left does not equal the limit from the right.
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bard
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lim(x->pi/4) tan(2x) =tan(pi/2) wat to do after this, it is undefined
 
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tan(pi/2) is undefined but the limit is not. take a look at a graph of tan(x) and see what's going on just to the left or right of pi/2.
 
  • #3
Actually the limit is not defined. As x approaches [itex]\frac{\pi}{2}[/itex] from the left, the function approaches infinity. As x approaches from the right, the function approaches negative infinity. The limit from the left does not equal the limit from the right, so the limit does not exist. Actually, strictly speaking, the limit would not exist even if the function approached positive infinty from both sides, since the definition of the limit requires that the function get arbitrarily close to the limit, and it is impossible for a function to be within some definite value of infinty.
 

1. How do you solve for the limit lim(x->pi/4) tan(2x) =tan(pi/2)?

To solve this limit, we can use the trigonometric identity tan(2x) = 2tan(x)/(1-tan^2(x)). Substituting x=pi/4, we get 2tan(pi/4)/(1-tan^2(pi/4)). Using the fact that tan(pi/4)=1, we get 2/(1-1)=2/0. Since the denominator is approaching 0, we can use L'Hopital's rule to get the limit as 2. Therefore, lim(x->pi/4) tan(2x) = 2.

2. Can we use the Squeeze Theorem to solve for this limit?

No, the Squeeze Theorem can only be used for finding limits as x approaches a specific value, not as it approaches infinity or a multiple of pi.

3. What is the value of the limit lim(x->pi/4) tan(2x) when x is approaching from the left and from the right?

When approaching from the left, the value of the limit is 2. However, when approaching from the right, the value of the limit does not exist as the function tan(2x) oscillates between positive and negative infinity.

4. Is it possible to solve this limit without using L'Hopital's rule?

Yes, we can also use the trigonometric identity tan(2x) = sin(2x)/cos(2x). Substituting x=pi/4, we get sin(pi/2)/cos(pi/2) = 1/0. Again, using L'Hopital's rule, we get the limit as 2.

5. What does it mean when a limit approaches a value that is undefined?

When a limit approaches a value that is undefined, it means that the function is approaching either positive or negative infinity, and does not have a finite value at that point.

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