amaths

👨🏻‍🏫 學術台數學

2007-02-22 2:37 am

(1/√2)sinx + (1/√2)cosx <-------

= sin(π/4)sinx + cos(π/4)cosx

sin(π/4) = (√2)/2

但這裡不是1/√2嗎

回答 (2)

2007-02-22 2:40 am

✔ 最佳答案

sin(π/4) = (√2)/2 是對的
我們只要將1/√2有理化
(1/√2)(√2/√2)=√2/2
所以兩者是相等
兩者也是對的

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2007-02-22 3:58 am

1/√2

= 1/√2 (√2 /√2 )

=√2/2

So,

sin(π/4) = (√2)/2 = 1/√2

參考: BY EASON MENSA

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