Find the exact value of the expression for the given value of 0. Cos(20) if 0=pi/4?

👨🏻‍🏫 學術台數學

[匿名]

2017-04-12 1:20 pm

I know the answer ends up being 0, but i dont understand how 20=pi/2

please explain and help me understand how to solve fully

回答 (5)

用戶57802

2017-04-12 1:22 pm

✔ 最佳答案

Cos(20)=Cos(2(pi/4))=Cos(pi/2)=0

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胡雪8°

2017-04-12 1:24 pm

cos(2θ)
= cos[2 × (π/4)]
= cos(π/2)
= 0

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[匿名]

2017-04-12 7:48 pm

Well,

it is obvious that
if θ = pi/4
then
cos(2θ) = cos(2 * pi/4) = cos(pi/2) = 0

hope it' ll help !!

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[匿名]

2017-04-12 1:20 pm

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[匿名]

2017-04-12 1:20 pm

Yup

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