Question

Evaluate
f(x) = 8 sin x − 6 cos 2x
at x = π/6.
1. f(π/6) = 3√3
2. f(π/6) = 1
3. f(π/6) = 2√3
4. f(π/6) = 2
5. f(π/6) = √3
6. f(π/6) = 3

Answer 1

\[\sin \left( \frac{ \pi }{6 } \right) = \frac{ 1 }{ 2 }\]

Answer 2

\[\cos \left( \frac{ 2\pi }{ 6} \right) = \cos \left( \frac{ \pi }{ 3} \right) = \frac{ 1 }{ 2}\]

Answer 3

We know this from the unit circle.

Answer 4

\[8\left( \frac{ 1 }{ 2 } \right) - 6\left( \frac{ 1 }{ 2 } \right)\]

Answer 5

4-3 = 1