integration of sin x/sin x+cos x dx.
Answers
Step-by-step explanation:
Given ∫{sinx/(sinx+cosx)}dx
= (1/2)*∫{2sinx/(sinx+cosx)}dx
= (1/2)*∫{(2sinx+cosx-cosx)/(sinx+cosx)}dx
= (1/2)*∫{(sinx+sinx+cosx-cosx)/(sinx+cosx)}dx
= (1/2)*∫{(sinx+cosx +sinx-cosx)/(sinx+cosx)}dx
= (1/2)*∫{1 + (sinx-cosx)/(sinx+cosx)}dx
Let sinx + cosx = t
Differentiate with respect to x
(cosx - sinx)dx = dt
=> - (sinx - cosx)dx = dt
=> (sinx - cosx)dx = -dt
Now (1/2)*∫{1 + (sinx-cosx)/(sinx+cosx)}dx = -(1/2)*∫{1 + 1/t }dt
= -(1/2)*[x + logt] + c
= -(1/2)*[x + log(sinx + cosx)] + c (By putting sinx + cosx = t)
So ∫{sinx/(sinx+cosx)}dx = -(1/2)*[x + log(sinx + cosx)] + c
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Answer:
Given ∫{sinx/(sinx+cosx)}dx
= (1/2)*∫{2sinx/(sinx+cosx)}dx
= (1/2)*∫{(2sinx+cosx-cosx)/(sinx+cosx)}dx
= (1/2)*∫{(sinx+sinx+cosx-cosx)/(sinx+cosx)}dx
= (1/2)*∫{(sinx+cosx +sinx-cosx)/(sinx+cosx)}dx
= (1/2)*∫{1 + (sinx-cosx)/(sinx+cosx)}dx
Let sinx + cosx = t
Differentiate with respect to x
(cosx - sinx)dx = dt
=> - (sinx - cosx)dx = dt
=> (sinx - cosx)dx = -dt
Now (1/2)*∫{1 + (sinx-cosx)/(sinx+cosx)}dx = -(1/2)*∫{1 + 1/t }dt
= -(1/2)*[x + logt] + c
= -(1/2)*[x + log(sinx + cosx)] + c (By putting sinx + cosx = t)
So ∫{sinx/(sinx+cosx)}dx = -(1/2)*[x + log(sinx + cosx)] + c