Math21 Trigonometry Double, Half-Angle Identities
If sinθ = 1/3, and 0<θ<π/2, find the exact value of tan2θ
(4√2)/7
If sinθ = 1/3, and 0<θ<π/2, find the exact value of sin2θ
(4√2)/9
If secθ = -4/3, and 90°<θ<180°, find the exact value of sin2θ
-(3√7)/8
Use a half-angle identity to find the exact value of cos(7π/12)
-√(2-√3)/2
If secθ = -4/3, and 90°<θ<180°, find the exact value of cos2θ
1/8
Use a half-angle identity to find the exact value of tan(5π/12)
2 + √3
If secθ = -4/3, and 90°<θ<180°, find the exact value of tan2θ
3√7
If sinθ = 1/3, and 0<θ<π/2, find the exact value of cos2θ
7/9
If θ is an angle in Quadrant I, and cosθ = 1/4, find tan(θ/2)
√(15)/5
Use a half-angle identity to find the exact value of tan(π/8)
√(2) - 1
Use a half-angle identity to find the exact value of cos15°
√(2+√3)/2
Use a half-angle identity to find the exact value of sin(π/8)
√(2-√2)/2