If sin(θ)+cos(θ)=12\sin(\theta) + \cos(\theta) = \frac{1}{2}sin(θ)+cos(θ)=21, what is the value of sin3(θ)+cos3(θ)\sin^3(\theta) + \cos^3(\theta)sin3(θ)+cos3(θ)?
1116\frac{11}{16}1611
716\frac{7}{16}167
1316\frac{13}{16}1613
916\frac{9}{16}169