Integrate int (sin^2(t) + cos^2(t) -1)dt from e^x to e^(2x)

In summary, the conversation discusses the integration problem of (sin^2(t) + cos^2(t) -1)dt from e^x to e^2x, with some confusion about a possible trigonometric identity involved. It is eventually determined that the solution is 0. Another integration problem is proposed, \int_0^{ln(1)} sin(x)e^{-x^{2}}dx, with a hint given and some discussion about the limits of integration.
  • #1
cooltee13
25
0

Homework Statement



Integrate from e^x to e^2x: (sin^2(t) + cos^2(t) -1)dt

Homework Equations


just standard integral equations


The Attempt at a Solution



I know how to do most of it, my only question is: is (sin^2(e^2x) + cos^2(e^x) -1) a special trig identity? or would i just solve it like a normal interation in parts problem?
 
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  • #2
well it seems trivial to me... lol
This question seems to be just tricky, nothing else.
 
  • #3
Aren't the sin and cos together adding to 1 the way you've written it, thus 1-1=0 ? You may want to double check you have it correct
 
  • #4
[tex]\int_{e^{x}}^{e^{2x}}(sin^{2}(t)+cos^{2}(t)-1)dt=\int_{e^{x}}^{e^{2x}}(1-1)dt=\int_{e^{x}}^{e^{2x}}(0)dt=?[/tex]

What does this equal to??
 
  • #5
ok, thanks guys lol. I feel dumb now
 
  • #6
cooltee13 said:
ok, thanks guys lol. I feel dumb now

Ok, integrate the following:

[tex]\int_0^{ln(1)} sin(x)e^{-x^{2}}dx[/tex]

This question was somewhere i don't know where though. Give a shot to it.

HINT: THis is also tricky.
 
Last edited:
  • #7
sutupidmath said:
[tex]\int_{e^{x}}^{e^{2x}}(sin^{2}(t)+cos^{2}(t)-1)dt=\int_{e^{x}}^{e^{2x}}(1-1)dt=\int_{e^{x}}^{e^{2x}}(0)dt=?[/tex]

What does this equal to??
Isnt that just equal to 1?
 
  • #8
Look at your limits of Integration

From 0 to Ln(1)
 
  • #9
cooltee13 said:
Isnt that just equal to 1?

Why on Earth do u think it is equal to 1?
 
  • #10
rocomath said:
Look at your limits of Integration

From 0 to Ln(1)
How did u change your display name?
 

1. What is the purpose of integrating the expression (sin^2(t) + cos^2(t) -1)?

The purpose of integrating this expression is to find the area under the curve of the given function. This can help in calculating values such as displacement, velocity, and acceleration in physics or finding the probability of certain events in statistics.

2. Why is the integration being done from e^x to e^(2x)?

The limits of integration, e^x and e^(2x), are chosen based on the given function and the desired outcome. In this case, they could represent the starting and ending points of a physical movement or the range of values in a statistical experiment.

3. How do you solve the integral of (sin^2(t) + cos^2(t) -1)?

This integral can be solved using basic integration techniques, such as the power rule and trigonometric identities. By expanding the expression and simplifying, the integral can be reduced to a basic form that can be easily integrated.

4. Can you explain the meaning of the result obtained from the integration?

The result obtained from the integration represents the total area under the curve of the given function. This could have a physical interpretation, such as the displacement of an object, or a statistical interpretation, such as the probability of an event occurring within a certain range.

5. What are some real-world applications of integrating this expression?

The integration of this expression can be applied in various fields, such as physics, engineering, economics, and statistics. For example, it can be used to calculate the work done by a force, the profit or loss of a business over a period of time, or the probability of an event occurring within a given range of values.

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