How to solve these integrals? sqrt(a^2 + x^2) & sqrt(2 + x^2)?

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In summary, to solve these integrals without a calculator, you can use the substitution x = a \sinh(\theta) or a trig substitution x = a tan(\theta). This will simplify the integrand and allow you to solve for the numerical values using the identities a^2+ x^2= a^2 sec^2(\theta) and \sqrt{a^2+ x^2}= |a sec(x)|. The same method can be applied to the second problem with a= \sqrt{2}.
  • #1
srk999
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How to solve these integrals, such as- sqrt(a^2 + x^2) & sqrt(2 + x^2)

Please be as descriptive and simple as possible.

Please use only sin and cos if possible We are not allowed a calculator in the exam and will have to find numerical values.
 
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For the first: try the substitution [tex]x = a \sinh(\theta) = a\frac{e^{\theta}-e^{-\theta}}{2}[/tex]
 
  • #3
Or use a trig substitution: [itex]x= a tan(\theta)[/itex]. Then [itex]a^2+ x^2= a^2+ a^2tan^2(\theta)[/itex][itex]= a^2(1+ tan^2(\theta))= a^2 sec^2(\theta)[/itex]. [itex]\sqrt{a^2+ x^2}= |a sec(x)|.

And, of course, [itex]dx= a(tan(\theta))' d\theta= a sec^2(\theta)d\theta[/itex]

I hope you recognize that the second problem, with [itex]\sqrt{2+ x^2}[/itex], is exactly the same as the first problem with [itex]a= \sqrt{2}[/itiex].
 

1. How do you approach solving integrals with square root terms?

When dealing with integrals that contain square root terms, it is important to first try to simplify the expression. This can be done by factoring out any common factors or using trigonometric identities. If the integral cannot be simplified, then substitution or integration by parts may be necessary.

2. What is the general strategy for solving integrals with square root terms?

The general strategy for solving integrals with square root terms is to first try to simplify the expression, then use substitution or integration by parts if necessary. If the integral cannot be solved using these methods, then numerical approximation techniques may be used.

3. How do you solve integrals of the form ∫sqrt(a^2 + x^2) dx?

To solve integrals of the form ∫sqrt(a^2 + x^2) dx, we can use the trigonometric substitution x = a tan u. This will result in the integral becoming ∫a sec^2 u du, which can be easily solved using basic integration rules.

4. Can you provide an example of solving an integral with the form ∫sqrt(a^2 + x^2) dx?

As an example, let's solve the integral ∫sqrt(4 + x^2) dx. We can use the trigonometric substitution x = 2 tan u. This will result in the integral becoming ∫2 sec^2 u du. Using the formula for integrating sec^2 u, we get 2 tan u + C. Substituting back in for u and simplifying, we get the final answer of 2x + 2√(4 + x^2) + C.

5. How do you solve integrals of the form ∫sqrt(2 + x^2) dx?

Integrals of the form ∫sqrt(2 + x^2) dx can be solved using the substitution x = √2 tan u. This will result in the integral becoming ∫√2 sec^2 u du. We can then use the formula for integrating sec^2 u to get √2 tan u + C. Substituting back in for u and simplifying, we get the final answer of √2x + 2√(2 + x^2) + C.

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