Integral: Solve $\int \frac{\sin x+\cos x}{\sec x+ \tan x}dx$

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SUMMARY

The integral $\int \frac{\sin x+\cos x}{\sec x+ \tan x}dx$ can be simplified by expressing all terms in terms of sine and cosine functions. Key identities include $\sec x = \frac{1}{\cos x}$ and $\tan x = \frac{\sin x}{\cos x}$. The discussion emphasizes the importance of rewriting the integral using these identities and suggests using the Weierstrass substitution, $t = \tan \frac{x}{2}$, to facilitate integration. Participants noted the necessity of correctly applying trigonometric identities to solve the integral effectively.

PREREQUISITES
  • Understanding of trigonometric identities, specifically $\sec x$ and $\tan x$.
  • Familiarity with integration techniques, including substitution methods.
  • Knowledge of the Weierstrass substitution for integrals.
  • Ability to manipulate expressions involving sine and cosine functions.
NEXT STEPS
  • Study the Weierstrass substitution technique in detail.
  • Practice rewriting integrals using trigonometric identities.
  • Learn about the integration of trigonometric functions, particularly $\sin^2 x$ and $\sin 2x$.
  • Explore advanced integration techniques, including integration by parts and substitution methods.
USEFUL FOR

Students studying calculus, particularly those focusing on integral calculus and trigonometric integrals, as well as educators looking for effective teaching strategies for these topics.

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Homework Statement


\int \frac{\sin x+\cos x}{\sec x+ \tan x}dx

Homework Equations



\sin x = \frac{1}{\sec x}
\cos x = \frac{\sin x}{\tan x}


The Attempt at a Solution


i separate and try to use identities but i got nothign

1/(secx^2+secx tan x)+sin x/tanx^2+sec x :confused:
 
Last edited:
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write everything in terms of sin x and cos x only, then integrate with change of variable.
 
One of your identities is incorrect: sec(x)=1/cos(x).

As has been said above, you should first look to express everything in terms of sines and cosines. See if this gives you a hint as to how to proceed.
 
please tell more

this is the shape that i got
don't know how to complete

–integral sin²x-sin2x-1/2(1+sinx)
 
-(\int \sin^2 x dx - \int \sin 2x dx - 1/2\int 1+\sin x)

Write sin^2 x as (1/2) (1-cos2x).

for sin 2x, make a substitution u=2x, then remember the integral of sin u is -cos u.

For the 3rd one, if you can't do it, why are you doing this question?
 
you can also try weierstrass substitution
i.e t = tan x/2
 

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