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Reference Angles

Reference Angles. Yes, they are this important. θ is called the reference angle. reference angle. ( – 1, 2). The acute angle made between the terminal side ( r ). r. and the x -axis. α. θ. θ is called the reference angle. Be careful when calculating this.

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Reference Angles

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  1. Reference Angles Yes, they are this important

  2. θ is called the reference angle reference angle (–1, 2) The acute angle made between the terminal side (r) r and the x-axis α θ

  3. θ is called the reference angle Be careful when calculating this. When you’re in Q II, you need to subtract from 180° to find the reference angle r α θ

  4. α θ is called the reference angle θ When you’re in Q III, you need to subtract 180° to find the reference angle r

  5. θ is called the reference angle θ α When you’re in Q IV, you need to subtract from 360° to find the reference angle r

  6. Since the cosine is negative, α will be in QII and III Find the values of α • Remember that in QI α α θ θ This is where we can use the reference angle θ = 45° θ = ?

  7. Since tan is positive, α will be in Quadrants I and III Find all possible values of α • Remember that in QI α θ α θ The reference angle here is θ = ? θ = 30° So our solutions are and

  8. But what are these? They account for all the angles coterminal to 30° and 210° and Find all possible values of α α θ α θ Can we write these as one equation?

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