30 cos(0.5arccos0.62)

Question

30 cos(0.5arccos0.62)

Answer 1

30 cos(0.5arccos0.62)=27
30*√1+cos(arccos(0.62)/2=30*√1.62/2=30*0.9

Comments

а решение можно?

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да надо разложить cos по формуле cos(x/2)

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cos(x/2)=sqrt((1+cos2x)/2)

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cos(arccosx)=x