Question
Question: \[\int_{}^{}{\text{cos} ⥂ \text{e}\text{c}^{4}x}dx\]...
∫cos⥂ec4xdx
A
cotx+3cot3x+c
B
tanx+3tan3x+c
C
cotx−3cot3x+c
D
−tanx−3tan3x+c
Answer
cotx−3cot3x+c
Explanation
Solution
∫cos⥂ec4xdx=
∫cosec2x(1+cot2x)dx
=−cotx+3(cotx)3+c.