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int(sin x - cos x)/(sqrt(sin2x)) dx =...

`int(sin x - cos x)/(sqrt(sin2x)) dx ` =

A

`"log"{(sin x + cos x) + sqrt(sin 2x)}`

B

`- log {sin x + cos x + sqrt(sin 2x)}`

C

`log (sin x - cos x + sqrt(sin 2x))`

D

`- log [sin x - cos x + sqrt(sin 2x)]`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the integral \[ \int \frac{\sin x - \cos x}{\sqrt{\sin 2x}} \, dx, \] we will follow these steps: ### Step 1: Rewrite the Denominator First, we recognize that \[ \sin 2x = 2 \sin x \cos x. \] Thus, we can rewrite the integral as: \[ \int \frac{\sin x - \cos x}{\sqrt{2 \sin x \cos x}} \, dx. \] ### Step 2: Simplify the Integral Next, we can simplify the expression under the square root: \[ \sqrt{2 \sin x \cos x} = \sqrt{2} \sqrt{\sin x \cos x}. \] So, the integral becomes: \[ \int \frac{\sin x - \cos x}{\sqrt{2} \sqrt{\sin x \cos x}} \, dx = \frac{1}{\sqrt{2}} \int \frac{\sin x - \cos x}{\sqrt{\sin x \cos x}} \, dx. \] ### Step 3: Use Substitution Now, we can use the substitution \( t = \sin x + \cos x \). The derivative of \( t \) is: \[ dt = (\cos x - \sin x) \, dx. \] Thus, we can express \( dx \) as: \[ dx = \frac{dt}{\cos x - \sin x}. \] ### Step 4: Express \(\sin x - \cos x\) in terms of \(t\) Notice that: \[ \sin x - \cos x = -(\cos x - \sin x). \] Now substituting into the integral, we have: \[ \int \frac{\sin x - \cos x}{\sqrt{\sin x \cos x}} \, dx = -\int \frac{1}{\sqrt{\sin x \cos x}} \cdot \frac{dt}{\cos x - \sin x}. \] ### Step 5: Rewrite \(\sqrt{\sin x \cos x}\) Using the identity \(\sin x \cos x = \frac{1}{2} \sin 2x\), we can rewrite: \[ \sqrt{\sin x \cos x} = \sqrt{\frac{1}{2} \sin 2x} = \frac{1}{\sqrt{2}} \sqrt{\sin 2x}. \] ### Step 6: Substitute Back into the Integral Now, substituting back into the integral gives: \[ -\int \frac{1}{\sqrt{\frac{1}{2} \sin 2x}} \cdot \frac{dt}{\cos x - \sin x}. \] ### Step 7: Solve the Integral Using the formula for the integral of the form \(\int \frac{1}{\sqrt{x^2 - a^2}} \, dx\), we can solve the integral: \[ -\log(t + \sqrt{t^2 - 1}) + C. \] ### Step 8: Substitute Back for \(t\) Finally, substituting back \(t = \sin x + \cos x\): \[ -\log(\sin x + \cos x + \sqrt{(\sin x + \cos x)^2 - 1}) + C. \] ### Final Answer Thus, the final answer is: \[ -\log(\sin x + \cos x + \sqrt{\sin^2 x + \cos^2 x}) + C = -\log(\sin x + \cos x + 1) + C. \]
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