\(∫
cos
e
c
(
x
−
a
)
cos
e
c
x
d
x
=\)
\(\frac{1}{\sin a} \log \left[ \sin(x - a) .cosec x \right]
\)
\(\frac{1}{\sin a} \log \left[ \sin(x - a) \cdot \sin x \right]\)
\(-\frac{1}{\sin a} \log \left[ \sin x \cdot cosec(x - a) \right]
\)
\(-\frac{1}{\sin a} \log \left[ \sin(x - a) \cdot \sin x \right]\)
