cos1110 °

1110° is three lots of 360° with 30° left over, so cos(1110°) is the same as cos(30°), which is (√3)/2  

(in decimal form this is as given by Shaomada)

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the site you are posting this on (http://web2.0calc.com/) is a calculator. Press the button which has 'cos' printed on it, 3 times the '1' button, 1 time the '0' button and finally one time the ')' button. The top field should now show cos(1110). Make sure you have degree selected in the button left and press '='. The calculator will now correctly calculate $$cos(1110^\circ)=0.866025403784$$. Easy if you know how to use a calculator.