Finding the limits of this expression

  • Thread starter Thread starter unscientific
  • Start date Start date
  • Tags Tags
    Expression Limits
Click For Summary
SUMMARY

The discussion centers on evaluating two attempts to solve a mathematical expression involving the derivative of an anti-derivative of sin(x)/x. The key distinction made is that in Attempt 1, the derivative F(2)' is incorrectly equated to F'(2), while Attempt 2 correctly identifies that F(2)' does not equal F'(2). The conclusion emphasizes that both attempts yield the average value of sin(x)/x near x=2, resulting in sin(2)/2.

PREREQUISITES
  • Understanding of calculus, specifically derivatives and anti-derivatives.
  • Familiarity with Taylor series expansions.
  • Knowledge of the function sin(x)/x and its properties.
  • Ability to analyze mathematical expressions rigorously.
NEXT STEPS
  • Study the properties of the function sin(x)/x and its behavior near x=2.
  • Learn about Taylor series and their applications in approximating functions.
  • Explore the concept of derivatives of anti-derivatives in calculus.
  • Investigate common pitfalls in differentiating constant terms in Taylor expansions.
USEFUL FOR

Students and educators in mathematics, particularly those focusing on calculus and analysis, as well as anyone looking to deepen their understanding of derivatives and Taylor series.

unscientific
Messages
1,728
Reaction score
13

Homework Statement



I did two attempts. I find attempt no. 1 slightly fishy and attempt 2 more rigorous. Can anyone tell me what's wrong with attempt no. 1?



The Attempt at a Solution



Attempt no. 1:
v6nqcy.png


Attempt no. 2:
357keme.png
 
Physics news on Phys.org
They are both basically right. In one though
(F(x)-F(2))'=F'(x)-0=f(x)
F(2)' is not equal to F'(2)

This can be seen as the derivative of the anti-derivative of sin(x)/x

or the average of sin(x)/x over x near 2

in either case we get

sin(2)/2
 
lurflurf said:
They are both basically right. In one though
(F(x)-F(2))'=F'(x)-0=f(x)
F(2)' is not equal to F'(2)

This can be seen as the derivative of the anti-derivative of sin(x)/x

or the average of sin(x)/x over x near 2

in either case we get

sin(2)/2

An example of F'(2) would be say...the first f' term in the taylor's expansion. F(2)' would be say, differentiating the constant term in taylor's expansion.

I see what you mean..thanks!
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
3K
Replies
3
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K