SOLUTION: if tan 0= 2/3 and angle 0 is a principal angle that lies in a quadrant 3 such that 0° ≤ θ ≤ 360°, determine cos 0 and sin 0

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Question 1199614: if tan 0= 2/3 and angle 0 is a principal angle that lies in a quadrant 3 such that 0° ≤ θ ≤ 360°, determine cos 0 and sin 0
Found 2 solutions by ikleyn, MathTherapy:
Answer by ikleyn(52780) About Me  (Show Source):
You can put this solution on YOUR website!
.
if tan(a)= 2/3 and angle "a" is a principal angle that lies in highlight%28cross%28a%29%29 quadrant 3
such that 0° ≤ a ≤ 360°, determine cos(a) and sin(a)
~~~~~~~~~~~~~~~~~~~

Right angled triangle with the legs 2 and 3;  the hypotenuse is  sqrt%282%5E2%2B3%5E2%29 = sqrt%2813%29.


sin(a) is -2%2Fsqrt%2813%29;  sign "minus" is because angle "a" is in QIII.


cos(a) is -3%2Fsqrt%2813%29;  sign "minus" is due to the same reason.

Solved.



Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
if tan 0= 2/3 and angle 0 is a principal angle that lies in a quadrant 3 such that 0° ≤ θ ≤ 360°, determine cos 0 and sin 0

As θ is in the 3rd quadrant, 

                
                                  matrix%281%2C3%2C+r%2C+%22=%22%2C+sqrt%2813%29%29

               We then get: