Tan(135°) = -1
Tangent — sine divided by cosine, equivalently opposite/adjacent in a right triangle; undefined where cos = 0.
How to derive tan(135°)
135° is in quadrant II. Reference angle = 45°, tangent negative in Q2, so tan(135°) = −tan(45°) = −1.
Unit-circle context
The angle 135° corresponds to 3π/4 radians and sits Quadrant II on the unit circle.
Its reference angle is 45°, which is why tan(135°) shares its absolute value with tan(45°).
Other trig values at 135°
Related tan values
Frequently asked
- What is the exact value of tan(135°)?
- The exact value is -1. Its decimal approximation is -1.
- How do you derive tan(135°)?
- 135° is in quadrant II. Reference angle = 45°, tangent negative in Q2, so tan(135°) = −tan(45°) = −1.
- What is 135° in radians?
- 135° equals 3π/4 radians (multiply degrees by π/180).
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