Topic explanation

Standard explanation

Trig functions are periodic, so restrict their domains before defining one-valued inverses.

Key points

• Why principal values are needed
• rule
• worked example
• Why principal values are needed: Trig functions are periodic, so restrict their domains before defining one-valued inverses.
• CONCEPT AND RULE: Trig functions are periodic, so restrict their domains before defining one-valued inverses.
• METHOD: For why principal values are needed, identify the given information and required result. Select the
• Trig functions are periodic, so restrict their domains before defining one-valued inverses.
• Worked pattern: sin x is restricted to [-pi/2,pi/2] for arcsin.

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