Free · Worked example · 49 problems · Answer key · US Letter
How to do it
Find the reference angle and its value, then the sign from the quadrant: sine is positive in I and II, cosine in I and IV, tangent in I and III.
tan43π=−1 reference angle 4π, quadrant II: tan is negative there Example problems
- sin47π=
- cos47π=
- sin45π=
- tan135∘=
Trigonometry
- Right triangle trigonometry: sin, cos and tan
- Special right triangles and exact trig values
- Converting degrees and radians
- The unit circle
- Amplitude and period
- The Pythagorean identity
- Simplifying trig expressions with identities
- Solving trigonometric equations
- The law of cosines
- The law of sines