Question

cotx=-4
The answers are x=2.90 and x=6.04
I don't understand why the angles will be in the second and third quads?

Answer 1

Remember that

cotangent = cosine/sine

or

cot = cos/sin

------------------------

so if cot is negative, then either

a) cos is negative and sin is positive

or

b) cos is positive and sin is negative

Both sin and cos can't be positive or negative (one must be positive, the other must be negative)

So this would place the angles in Q 2 (where cos is neg, sin is pos) and in Q 4 (cos is pos, sin is neg)