Sunday, 30 August 2015

calculus - Finding value of given integral



Find the value of the following integral. tanx1/etdt1+t2+cotx1/edt1+t2



As a start, I've done this -



tanx1/etdt1+t21/ecotxdt1+t2=tanxcotxt11+t2dt




Is this valid? If yes, then how to proceed?


Answer



tanx1/etdt1+t2+cotx1/edt1+t2



For the first integral, substitute 1+t2=stdt=ds2. Also, we know that 11+t2dt=arctant+c. We thus get: tanx1/eds2s+arctan(cotx)arctan(1e) =12(lntanx+1)+arctan(cotx)arctan(1e)


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