Simplifying the Integral of 20 sec^3(x) dx using Trigonometric Identities

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In summary, the conversation is about finding the integral of 20 sec^3(x)dx using trigonometric identities. The speaker is having trouble breaking it down, but after using the substitution u = sin(x), they are able to solve the integral. They also mention that they have never seen this method before and find it cool.
  • #1
dexstarr
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I'm having a hard time breaking this down using tri identities.

} = integral sign 20}sec^3(x) dx
20}sec^2(x) * sec(x) dx
20}[tan^2(x)-1] * sec(x) dx

after this I'm stuck. I tried letting u = tan(x) or sec(x) but i can't seem to cancel anything out.
 
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  • #2
Re: Integral of 20 sec^3(x)dx

dexstarr said:
I'm having a hard time breaking this down using tri identities.

} = integral sign 20}sec^3(x) dx
20}sec^2(x) * sec(x) dx
20}[tan^2(x)-1] * sec(x) dx

after this I'm stuck. I tried letting u = tan(x) or sec(x) but i can't seem to cancel anything out.

\(\displaystyle 20 \int \frac{1}{\cos^3(x)}\)

Multiply by \(\displaystyle \dfrac{\cos(x)}{\cos(x)}\)

\(\displaystyle 20 \int \frac{\cos(x)}{\cos^4(x)}\)

\(\displaystyle 20 \int \frac{\cos(x)}{(1-\sin^2(x))^2}\)

Now use \(\displaystyle u = \sin(x)\)
 
  • #3
Re: Integral of 20 sec^3(x)dx

SuperSonic4 said:
Multiply by \(\displaystyle \dfrac{\cos(x)}{\cos(x)}\)
Coooool! I've never seen that method.

-Dan
 

Related to Simplifying the Integral of 20 sec^3(x) dx using Trigonometric Identities

1. What is the formula for the integral of 20 sec³(x) dx?

The formula for the integral of 20 sec³(x) dx is 20 tan(x) + 20 ln|sec(x)+tan(x)| + C, where C is the constant of integration.

2. How do you solve the integral of 20 sec³(x) dx?

To solve the integral of 20 sec³(x) dx, you can use the substitution method or integration by parts. Alternatively, you can also use a trigonometric identity to simplify the integral.

3. Can the integral of 20 sec³(x) dx be solved by hand?

Yes, the integral of 20 sec³(x) dx can be solved by hand using various integration techniques. However, it may be more efficient to use a graphing calculator or computer software to find the exact solution.

4. What is the significance of the integral of 20 sec³(x) dx in mathematics?

The integral of 20 sec³(x) dx is significant in mathematics as it represents the area under the curve of the function 20 sec³(x). It is also frequently used in physics and engineering to solve problems involving periodic functions.

5. How can the integral of 20 sec³(x) dx be applied in real-world scenarios?

The integral of 20 sec³(x) dx has various applications in real-world scenarios, such as calculating the displacement of a pendulum, determining the frequency of a sound wave, and analyzing the motion of a swinging object. It is also used in fields such as optics, acoustics, and electrical engineering.

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