Find the angle `theta` whose cosine is equal to its tangent.

Find the angle which is equal to its supplement.

Find the angle which is equal to its complement

Find the angle which is equal to its supplement

Find the angle whose complement is one third of its supplement.

Find the angle whose supplement is four times its complement.

Find the angle between the lines whose direction cosines are connected by the relations l+m+n=0and2lm+2nl-mn=0

Find the angle between the vectors whose direction cosines are proportional to 2,3,-6 and 3,-4,5

Find the angle between the lines whose direction-cosines are give /+2m+3n=0 and 3/m-4/n+mn=0'

Find the angle between the two lines whose direction cosines are: (2)/(3),(-1)/(3),(-2)/(3) and (3)/(7),(2)/(7),(6)/(7) .