Question
exact value of
cot[arccos(-2/3)]
cot[arccos(-2/3)]
Answers
MathMate
cos(θ)=-2/3
So θ is in the second or third quadrant. There is not enough information to be sure of which.
adjacent = -2
hypotenuse = 3
opposite = ±√(3²-(-2)²)
= ±√(5)
Therefore
cot(θ)
=adjacent/opposite
=-2/(±√(5))
= ±(2/√(5))
=±(2√(5)/5)
So θ is in the second or third quadrant. There is not enough information to be sure of which.
adjacent = -2
hypotenuse = 3
opposite = ±√(3²-(-2)²)
= ±√(5)
Therefore
cot(θ)
=adjacent/opposite
=-2/(±√(5))
= ±(2/√(5))
=±(2√(5)/5)