The value of cos ⁡ 2 π 63 cos ⁡ 3 π 70 cos ⁡ 4 π 77 cos ⁡ π 72 cos ⁡ π 40 cos ⁡ 3 π 88 1 cos ⁡ π 90 cos ⁡ 2 π 99 is equal to

Question

The value of cos ⁡ 2 π 63 cos ⁡ 3 π 70 cos ⁡ 4 π 77 cos ⁡ π 72 cos ⁡ π 40 cos ⁡ 3 π 88 1 cos ⁡ π 90 cos ⁡ 2 π 99 is equal to, 0, 1, 2 cos ⁡ π 9, cos ⁡ π 11

MARKS App · Accepted Answer

The given determinant = cos ⁡ π 7 - π 9 cos ⁡ π 7 - π 10 cos ⁡ π 7 - π 11 cos ⁡ π 8 - π 9 cos ⁡ π 8 - π 10 cos ⁡ π 8 - π 11 cos ⁡ π 9 - π 9 cos ⁡ π 9 - π 10 cos ⁡ π 9 - π 11 = cos ⁡ π 7 cos ⁡ π 9 + sin ⁡ π 7 sin ⁡ π 9 cos ⁡ π 7 cos ⁡ π 10 + sin ⁡ π 7 sin ⁡ π 10 cos ⁡ π 7 cos ⁡ π 11 + sin ⁡ π 7 sin ⁡ π 11 cos ⁡ π 8 cos ⁡ π 9 + sin ⁡ π 8 sin ⁡ π 9 cos ⁡ π 8 cos ⁡ π 10 + sin ⁡ π 8 sin ⁡ π 10 cos ⁡ π 8 cos ⁡ π 11 + sin ⁡ π 8 sin ⁡ π 11 cos ⁡ π 9 cos ⁡ π 9 + sin ⁡ π 9 sin ⁡ π 9 cos ⁡ π 9 cos ⁡ π 10 + sin ⁡ π 9 sin ⁡ π 10 cos ⁡ π 9 cos ⁡ π 11 + sin ⁡ π 9 sin ⁡ π 11 = cos ⁡ π 7 sin ⁡ π 7 0 cos ⁡ π 8 sin ⁡ π 8 0 cos ⁡ π 9 sin ⁡ π 9 0 cos ⁡ π 9 sin ⁡ π 9 0 cos ⁡ π 10 sin ⁡ π 10 0 cos ⁡ π 11 sin ⁡ π 11 0 = 0

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