Find the values of the following trigonometric ratio: `cos e c\ (-1200^0)`

Explanation

`cosec(-1200^{circ})=cosec(-(7 pi-frac{pi}{3}))`

`=cosec(7 pi-frac{pi}{3})`

`[therefore cosec(-theta)=-cosec theta] `

`=-cosec(2 times 3 pi+(pi-frac{pi}{3}))`

`=-cosec(pi-frac{pi}{3})`

`[therefore cosec` is periodic of period `2 pi, therefore cosec(2 pi+theta)=cosec(2 n pi+theta)`

`=cosec theta` foralln `in {N}]`

`=-cosec frac{pi}{3}`

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