How do we integrate cos(x)-sin²(x)/sin(x)*cos(x) plzzz ?

1 Answer
Mar 31, 2018

Assuming that you mean:

#int (cos(x)-sin^2(x))/(sin(x)cos(x)) dx#

Separate into two integrals:

#int (cos(x)-sin^2(x))/(sin(x)cos(x)) dx = int cos(x)/(sin(x)cos(x)) dx -int sin^2(x)/(sin(x)cos(x)) dx#

Cancel common factors in both integrals:

#int (cos(x)-sin^2(x))/(sin(x)cos(x)) dx = int cancel(cos(x))/(sin(x)cancel(cos(x))) dx -int sin^cancel(2)(x)/(cancel(sin(x))cos(x)) dx#

Remove the cancelled terms:

#int (cos(x)-sin^2(x))/(sin(x)cos(x)) dx = int 1/sin(x) dx -int sin(x)/cos(x) dx#

Substitute #1/sin(x) = csc(x)# and #sin(x)/cos(x) = tan(x)#:

#int (cos(x)-sin^2(x))/(sin(x)cos(x)) dx = int csc(x) dx -int tan(x) dx#

These integrals can be found in any list of integrals:

#int (cos(x)-sin^2(x))/(sin(x)cos(x)) dx = -ln(cot(x)+ csc(x)) +ln( cos(x))+ C#