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Sum & Difference Formulas. Warm-Up: Find the exact value of each. sin(390 °+120°) sin390° + sin120°. Objective: Be able to use sum & difference formulas to find trig functions of non-unit circle values, simplify, verify, solve, etc, etc.
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Sum & Difference Formulas • Warm-Up: Find the exact value of each. • sin(390°+120°) • sin390° + sin120° Objective: Be able to use sum & difference formulas to find trig functions of non-unit circle values, simplify, verify, solve, etc, etc. TS: Explicitly assess information and draw conclusions
Using Sum/Diff to Find Exact Values Find the sine for 285°, using the fact 285°=330° – 45°
Using Sum/Diff to Find Exact Values Find the cosine for
Using Sum/Diff to Find Exact Values Find tan(u+v) where sin(u) = -7/25 & cos(v) = -4/5. Both u & v are in quadrant III.
Using Sum/Diff to Simplify Write the expression as the sine, cosine or tangent of an angle. • cos(0.88)cos(0.34)+sin(0.88)sin(0.34) b)
Using Sum/Diff to Verify Verify the identity sin(x + y)sin(x – y) = sin2x – sin2y
You Try! Verify each identity • sin(3π - x) = sinx • cos(x + y) + cos(x - y) = 2cosxcosy 3) Solve for x in the interval [0, 2π) 4) 5)