No need for substitution. Of course it is more advisable on an elementary level .Hint: Try the substitution:
And the result will follow.
Yes, that's another possible form. Consider the identity:Thank you,
i solved it, using substitution:
\(\displaystyle u= (k*ctgθ)/(1-k^2 )\)
But, my result is:
\(\displaystyle ϕ=-arcsin((k∙ctgθ)/√(1-k^2 ))+c_2\)
\(\displaystyle ϕ=arccos((k∙ctgθ)/√(1-k^2 ))+c_2\)
Is this correct?