Question #8cd79

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Answer 1 · 2017-11-27T14:32:06

#1#

#cos^2(180^@)=cos180^@xxcos180^@#

#"note that "cos180^@=-1#

#rArrcos^2(180^@)=(-1)^2=1#

Answer 2 · 2017-11-27T14:32:14

The value of #cos^2(180)# is 1.

#cos^2(180) = cos(180) * cos(180)#

By the unit circle, #cos(180) = -1#

Substituting for #cos(180)# gives

#cos^2(180) = -1 * -1 = 1#