Understanding Trig Identities and Variations

In summary, The conversation is discussing the use of trig identities to simplify expressions involving sec x, csc x, cot x, and tan x. The speaker also mentions the relevance of knowing different variations of these identities.
  • #1
bobsmith76
336
0

Homework Statement



Screenshot2012-02-08at54843AM.png


I don't see how they're going from

sec x cot x to csc x

and

csc x tan x to sec x

The derivative of sec x is sec x tan x not csc x tan x
and the derivative of csc x is -csc x cot x

and if it's an identity then they didn't care to inform me of that at this website

http://www.sosmath.com/trig/Trig5/trig5/trig5.html
 
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  • #2
bobsmith76 said:

Homework Statement



Screenshot2012-02-08at54843AM.png


I don't see how they're going from

sec x cot x to csc x

and

csc x tan x to sec x

Express sec x, csc x, cot x and tan x in terms of sin x and cos x first.

The derivative of sec x is sec x tan x not csc x tan x
and the derivative of csc x is -csc x cot x

Sure, but what's the relevance of this? They weren't integrating at that stage, merely simplifying using trig identities.
 
  • #3
bobsmith76 said:

Homework Statement



Screenshot2012-02-08at54843AM.png


I don't see how they're going from

sec x cot x to csc x

and

csc x tan x to sec x

The derivative of sec x is sec x tan x not csc x tan x
and the derivative of csc x is -csc x cot x

and if it's an identity then they didn't care to inform me of that at this website

http://www.sosmath.com/trig/Trig5/trig5/trig5.html
You should not only recognize the trig identities, but different variations of them. For instance,
[itex]\tan \theta = \frac{\sin \theta}{\cos \theta}[/itex].
But it is also true that
[itex]\tan \theta = \sin \theta \sec \theta[/itex].
 

1. What are trigonometric antiderivatives?

Trigonometric antiderivatives are functions that represent the inverse operations of trigonometric derivatives. They are used to find the original function that was differentiated to get a given trigonometric function.

2. How do you find the antiderivative of a trigonometric function?

To find the antiderivative of a trigonometric function, you must use the reverse chain rule and the basic antiderivative formulas for trigonometric functions. It involves using substitution, integration by parts, or other integration techniques.

3. What are the basic antiderivative formulas for trigonometric functions?

The basic antiderivative formulas for trigonometric functions are:
- For sine: ∫ sin(x) dx = -cos(x) + C
- For cosine: ∫ cos(x) dx = sin(x) + C
- For tangent: ∫ tan(x) dx = -ln|cos(x)| + C
- For cotangent: ∫ cot(x) dx = ln|sin(x)| + C

4. How do you use trigonometric antiderivatives in real-world applications?

Trigonometric antiderivatives are used in various real-world applications, such as in physics, engineering, and finance. They can be used to model and solve problems involving periodic motion, such as the motion of a pendulum or a spring. They are also used in calculating areas and volumes of curved shapes, and in determining the growth and decay of certain processes.

5. Can all trigonometric functions have an antiderivative?

No, not all trigonometric functions have an antiderivative that can be expressed in terms of elementary functions. Some trigonometric functions, such as secant, cosecant, and their inverses, have more complex antiderivatives that cannot be written using basic formulas. These functions require advanced techniques, such as partial fractions or integration by parts, to find their antiderivatives.

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