Question

Explain how to find the value of sin \(\displaystyle{390}^{{\circ}}\) using periodic properties.

Answer 1

Step 1
Use \(\displaystyle{\sin{{\left({360}+\alpha\right)}}}={\sin{\alpha}}\)
Step 2
\(\displaystyle{\sin{{390}}}\)
\(\displaystyle={\sin{{\left({360}+{30}\right)}}}\)
\(\displaystyle={\sin{{30}}}\)
\(\displaystyle={\frac{{{1}}}{{{2}}}}={0.5}\)