Answer check, Hyperbolic trig identity (proof)

In summary, a hyperbolic trig identity is a mathematical relationship between hyperbolic functions that is similar to trigonometric identities. Proving these identities is important for establishing their validity and deepening our understanding of hyperbolic functions. The process involves using algebraic principles and the properties of hyperbolic functions. Common hyperbolic trig identities include those involving sinh, cosh, and tanh. These identities have practical applications in various fields, such as physics and engineering, for modeling and analyzing complex systems.
  • #1
bakin
58
0

Homework Statement


Evaluate the integral:
(int sign) Sech³xTanhx dx

Homework Equations


Derivative of Sechx = -(SechxTanhx)

The Attempt at a Solution



Rewrite as:
Sech²xSechxTanhx

U=sechx
Du = -(SechxTanhx)dx
-Du = SechxTanhx dx
replace into integral

-(integral sign) U²du

Evaluate:
-U³ / 3

answer = -Sech³x / 3

? It just seems like there should be more to it. What do you guys think?
 
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  • #2
Indeed there is more to it - a constant of integration. :wink:
 
  • #3
grr :mad:

Thanks :redface:
 
  • #4
it would have been much simpler if you had written everything in terms of sinh and cosh.

My 2ç
 

1. What is a hyperbolic trig identity?

A hyperbolic trig identity is a mathematical relationship between hyperbolic functions, such as sinh, cosh, and tanh. These identities are similar to the trigonometric identities but are specific to the hyperbolic functions.

2. Why is it important to prove hyperbolic trig identities?

Proving hyperbolic trig identities is important because it helps to establish the validity of these relationships and allows us to use them in solving mathematical problems. It also helps to deepen our understanding of hyperbolic functions and their properties.

3. What is the process for proving a hyperbolic trig identity?

The process for proving a hyperbolic trig identity involves manipulating the equations using algebraic principles and the properties of hyperbolic functions. This may include using double angle formulas, symmetry, and the definitions of hyperbolic functions.

4. What are some common hyperbolic trig identities?

Some common hyperbolic trig identities include:
- sinh²x + cosh²x = 1
- tanh(x + y) = (tanhx + tanhy) / (1 + tanhx * tanhy)
- cosh²x - sinh²x = 1
- sech²x = 1 - tanh²x
- sinh(x ± y) = sinhx * coshy ± coshx * sinhy
- cosh(x ± y) = coshx * coshy ± sinhx * sinhy

5. How can hyperbolic trig identities be used in real-world applications?

Hyperbolic trig identities can be used in various fields of science, such as physics, engineering, and economics. They are particularly useful in modeling and analyzing complex systems, such as vibrations, heat flow, and population growth. They can also be used in cryptography and signal processing.

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