Question

If

Answer 1

Answer:

• sin(-3π/4) = cos(-3π/4) = -(√2)/2
• tan(-3π/4) = 1

Step-by-step explanation:

The angle -3π/4 radians is a 3rd-quadrant angle, so the sine and cosine are both negative. The tangent is positive in that quadrant. The reference angle is the difference from -π, so is π/4.

  sin(π/4) = cos(π/4) = (√2)/2

The tangent is the ratio of sine to cosine. Since both are the same, the tangent is 1.

• sin(-3π/4) = -(√2)/2
• cos(-3π/4) = -(√2)/2
• tan(-3π/4) = 1

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Comment on the angle

This angle is equivalent to -135° or +225°. The reference angle is 45°. Since you have memorized the short table of trig functions, you know the trig functions of this angle.