The angle \theta_1θ
1
​
theta, start subscript, 1, end subscript is located in Quadrant \text{III}IIIstart text, I, I, I, end text, and \cos(\theta_1)=-\dfrac{5}{8}cos(θ
1
​
)=−
8
5
​
cosine, left parenthesis, theta, start subscript, 1, end subscript, right parenthesis, equals, minus, start fraction, 5, divided by, 8, end fraction .
What is the value of \sin(\theta_1)sin(θ
1
​
)sine, left parenthesis, theta, start subscript, 1, end subscript, right parenthesis?