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The value of cos 52^0+cos 68^0+cos 172^0...

The value of `cos 52^0+cos 68^0+cos 172^0` is `0` b. `1` c. `2` d. `3//2`

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`cos 52° + cos 68° + cos 172°`

`= cos(60° – 8°) + cos(60° + 8°) + cos(180° – 8°)`

Using the formula `cos(A + B) + cos(A – B) = 2 cos A cos B,`

`= 2 cos 60° cos 8° – cos 8°`

...
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