Use the angle difference identity to sovle 5cos2 (theta) = 1 for 0 degrees is less than or equal to theta is less than 360 degrees

Question

Brenda Schneider

Mathematics

1 February, 00:39

Use the angle difference identity to sovle 5cos2 (theta) = 1 for 0 degrees is less than or equal to theta is less than 360 degrees

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Dakota Camacho · Answer 1

Use cos (2∅) = 2cos² ∅ - 1

5 (2cos²∅ - 1) = 1

10cos²∅ - 5 = 1

10cos²∅ = 6

cos²∅ = 0.6

cos∅ = ± √ (0.6)

∅ = 39.2,180 - 39.2, 180 + 39.2, 360 - 39.2

∅ = 39.2, 140.8, 219.2, 320.8