Integration of dx/(x^2+ 2x+ 2)√(x^2+ 2x-4)?
Integration of dx/(x^2+ 2x+ 2)√(x^2+ 2x-4)?
Integration of dx/(x^2 + 2x + 2)√(x^2 + 2x - 4)
To integrate this expression, we can use a combination of algebraic manipulation and trigonometric substitution. Let's break down the solution into smaller steps.
Step 1: Simplify the expression
The first step is to simplify the expression by factoring the denominators and simplifying the square root:
x^2 + 2x + 2 can be factored as (x + 1)^2 + 1
x^2 + 2x - 4 can be factored as (x + 1)(x - 2)
So the expression becomes:
dx/((x + 1)^2 + 1)√((x + 1)(x - 2))
Step 2: Perform a trigonometric substitution
To simplify the expression further, let's substitute x + 1 = √2tanθ. This substitution will help us simplify the square root term.
Differentiating both sides with respect to x:
dx = √2sec^2θ dθ
Substituting this back into the expression, we get:
√2sec^2θ dθ/((√2tanθ)^2 + 1)√((√2tanθ + 1)(√2tanθ - 3))
Simplifying this further:
√2sec^2θ dθ/(2tan^2θ + 1)√((√2tanθ + 1)(√2tanθ - 3))
√2sec^2θ dθ/(2tan^2θ + 1)√(2tanθ - 3)(√2tanθ + 1)
Step 3: Substitute trigonometric identities
We can simplify the expression further using trigonometric identities. Let's use the following identities:
sec^2θ = 1 + tan^2θ
tan^2θ + 1 = sec^2θ
Substituting these identities into the expression, we get:
√2sec^2θ dθ/(sec^2θ)(2tanθ - 3)(√2tanθ + 1)
√2 dθ/(2tanθ - 3)(√2tanθ + 1)
Step 4: Integrate the expression
Now, we can integrate the expression. Let's break it down into partial fractions to simplify the integration:
√2 dθ/((2tanθ - 3)(√2tanθ + 1))
A/(2tanθ - 3) + B/(√2tanθ + 1)
To find the values of A and B, we multiply both sides by the denominators and equate the coefficients of like terms. After solving the equations, we find A = -√2/5 and B = √2/5.
Substituting these values back into the expression, we get:
(-√2/5)∫dθ/(2tanθ - 3) + (√2/5)∫dθ/(√2tanθ + 1)
Now, we can integrate each term separately using standard integral formulas or tables. After evaluating the integrals, we obtain the final solution.
Note: