Use a Reference Triangle in an Appropriate Quadrant to Find $\cos ^ { - 1 } \left( \frac { 1 } { \sqrt { 2 } } \right)$

question 389

Multiple Choice

Use a reference triangle in an appropriate quadrant to find the angle.
- $\cos ^ { - 1 } \left( \frac { 1 } { \sqrt { 2 } } \right)$

• A) \(\frac { 4 } { \pi }\)
• B) \(\frac { \pi } { 2 }\)
• C) \(\frac { 2 \pi } { 3 }\)
• D) \(\frac { 3 \pi } { 4 }\)

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