Question

οscar

求解（2）選項
怎麼算都覺得MB才是4(cos(45°-θ),sin(45-θ))
希望各界大神解答

-1-2-3-1-6-k
3. 如圖,以M為圓心、MA=4為半徑畫圓,E為該圓的直
徑,B、C、D三點皆在圓上,且AB=BC=CD=DE。若
sing
4 205 8
MC = 4(sin(0 +90°), cos(8+90°))。請選出正確的選項。
sim (90-0) - Los (0-0)
MA=4(sin 8, -cose) (2) MD = 4(cos(45°-0), sin(45°-0))
(PMA-MA=8
(4) MB ME = -8√2
me · MA = 0
b>k
MC = 4 (Cose, - Sine)
MA=
4 ( sind,
• + Cose)
5) BE = 4(cos(90°-0)-cos(45°-0), sin(90°-0)-sin(45°-0)) MF = 4 (-5ml -(osd)
(¹1)
MB = 4 (sin (f4fjs), cos (Bt
=4 (³5)
(2)
E
M
(0+135²)
MD = 4 [sin (0+ 135"), Lus (utlis)]
= 4 [_sin (45-0), -(05 (45²-0) ] ==
4 (Cos (0+45'), -sin (0+49")) = 4
(sin (45-8)
(4)
(5)
BE = B
1fr4x Cos 135²
17 sind - Cos'

高中數學 平面向量

Answer 1

✨ ベストアンサー ✨

qn

4(cosθ, -sinθ)=4(cos(-θ), sin(-θ))
寫成極座標剛好是 [4, -θ]
那MD就是 [4, 45°-θ]

οscar

哇！太猛了！
謝謝解答👍