Solving Int. with Trig Substitution for Beginners

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The discussion focuses on solving the integral ∫(√(1+x) + √(1-x)) / (√(1+x) - √(1-x)) dx using trigonometric substitution. Participants suggest that simplifying the expression algebraically is crucial, recommending the rationalization of the denominator by multiplying by (√(1-x) + √(1+x)). This approach leverages the identity (√(a) - √(b))(√(a) + √(b)) = a - b to facilitate further simplification. The original poster expresses a desire for guidance in calculus and finds the proposed method promising. Overall, the conversation emphasizes the importance of algebraic manipulation in solving integrals with trigonometric substitution.
stihl29
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Homework Statement


\int\frac{\sqrt{1+x}+\sqrt{1-x}} { \sqrt{1+x}-\sqrt{1-x}}{dx}


Homework Equations


I believe trig substitution can be used here. I'm not very good at calculus only beginning to take calc classes, and guideance would be wonderful. because i want to get better.


The Attempt at a Solution


I don't have any idea on what to substitute.
x = some thing like x^2 ??
or u = 1 - x
and u = 1 + x ??
 
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The first thing you want to do is simplify the expression algebraically. It will help to rationalize the denominator by multiplying numerator and denominator by sqrt(1-x)+sqrt(1+x). The trick here is that (sqrt(a)-sqrt(b))*(sqrt(a)+sqrt(b))=a-b. Try simplifying it and see how far you can get.
 
ohhhh, thank you, i can't attempt it at this moment but your solution looks promising !
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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