Find the values of the following trigonometric ratios.
`(i)cosec390^0`
(ii) `cot570^0`
(iii) `tan480^0`
(iv) `cos270^0`
(v) `tan(19pi)/3`
(vi) `sin((-11pi)/3)`
(vii) `cot(-15pi)/4`

Explanation

(i)`
begin{aligned}
operatorname{cosec} 390^{circ} &=operatorname{cosec}left(360^{circ}+30^{circ}right)
&=operatorname{cosec}left(90^{circ} times 4+30^{circ}right)
&=operatorname{cosec}left(30^{circ}right)
&=2
end{aligned}
`
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