Question 1182094
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determine the exact and simplified value of cos240°-2tan60°sec30°. 
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<pre>
cos(240°) = -cos(60°) = {{{-1/2}}}.


tan(60°) = {{{sqrt(3)}}}.


sec(30°) = {{{1/cos(30^o)}}} = {{{1/((sqrt(3)/2))}}} = {{{2/sqrt(3)}}}.



Therefore,  cos240°-2tan60°sec30° = {{{-1/2}}} - {{{2*(sqrt(3))*(2/sqrt(3))}}} = {{{-1/2}}} - 4 = - 4 {{{1/2}}} = - 4.5.    <U>ANSWER</U>
</pre>

Solved.