how b cos 120vanr315cor 225 cot 2 Solutioncos120 sin2315 c

how???

Solution

cos120 + sin²315 - cot(225)

cos( 180-60) + (sin(360-45))² - cot(270-45)

-cos 60 + ( -sin 45)² - tan(45)

-1/2 + 1/2 - 1

= -1

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[ formula used : cos( 180 - theta) = -cos (theta)

sin(360- theta) = -sin(theta)

cot(270 - theta) = tan(theta) ]