Respuesta :

In 3rd quadrant, sine function is negative.
So, sin theta = sqrt(1-(2/3)^2) = - sqrt(5) / 3

Answer:

[tex]\sin\theta=-\dfrac{\sqrt{5}}{3}[/tex]

Step-by-step explanation:

If θ is in Quadrant III

[tex]\cos\theta=-\dfrac{2}{3}[/tex]

As we know in III quadrant cosine and sine both are negative.

using trigonometry identity

[tex]\sin\theta=-\sqrt{1-\cos^2\theta}[/tex]

[tex]\sin\theta=-\sqrt{1-(\frac{2}{3})^2}[/tex]

[tex]\sin\theta=-\sqrt{1-\frac{4}{9}}[/tex]

[tex]\sin\theta=-\dfrac{\sqrt{5}}{3}[/tex]

Hence, The value of [tex]\sin\theta=-\dfrac{\sqrt{5}}{3}[/tex]