- #1
Mr Davis 97
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I am trying to evaluate the integral ##\displaystyle \int \frac{x}{1+\cos^2x}dx##. I have started by multiplying both the numerator and the denominator by ##\frac{\sin^2x}{\cos^4x}##, to get ##\displaystyle \int \frac{x\frac{\sin^2x}{\cos^4x}}{1+\tan^2x}dx##, and the denominator simplifies to sec^2, so we get ##\displaystyle \int x \tan^2x~dx##. Is my reasoning up to this point correct?