唔識做功課65

你有冇答案嫁？係唔係 (a) 同 (c) 係同一個答案？

2015-05-10 09:15:27 補充：
(a) PG＝PE＝√(2²＋2²＋4²)＝√24＝2√6GE＝√(4²＋4²)＝√32＝4√2the angle between PG and PE is：∠EPG
＝2 sin⁻¹(2√2 / 2√6)
＝70.5° (corr. to 3 sf)
(b) The projection of PG to the plane ABGF is GX, where X is the mid-pt of AB.As PX＝2, so,the angle between PG and the plane ABGF is：∠PGX＝sin⁻¹(2 / 2√6)＝24.1° (corr. to 3 sf)
(c) the angle between the planes ACG and ACE is：∠EPG＝70.5° (corr. to 3 sf, from (a))

係呀!冇錯!唔該晒你...

我覺得呢題有圖會好少少 0.0