- #1

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## Homework Statement

evaluate the integral.

## Homework Equations

[itex]\displaystyle\int {\frac{1}{secx+tanx} dx}[/itex]

## The Attempt at a Solution

can i just do ln|secx + tanx| ??

- Thread starter whatlifeforme
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- #1

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evaluate the integral.

[itex]\displaystyle\int {\frac{1}{secx+tanx} dx}[/itex]

can i just do ln|secx + tanx| ??

- #2

SammyS

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Probably not.## Homework Statement

evaluate the integral.

## Homework Equations

[itex]\displaystyle\int {\frac{1}{secx+tanx} dx}[/itex]

## The Attempt at a Solution

can i just do ln|secx + tanx| ??

What's the derivative of ln|secx + tanx| ?

Added in

Write the tangent in terms of sine & cosine and the secant as the reciprocal of the cosine.

Last edited:

- #3

Mark44

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No. You're making the same mistake you made in this thread: https://www.physicsforums.com/showthread.php?t=678488.## Homework Statement

evaluate the integral.

## Homework Equations

[itex]\displaystyle\int {\frac{1}{secx+tanx} dx}[/itex]

## The Attempt at a Solution

can i just do ln|secx + tanx| ??

It is NOT TRUE that

$$ \int \frac{dx}{f(x)} = ln|f(x)| + C$$

The above is true only if f(x) = x, which is certainly not the case here.

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