luthercymru's profile

Last login: 2 weeks agoLuthercymru: luthercymru is a 30 year old guy from Swansea, Wales, UK.; Likes 1,540 pages, 4 videos, 9 photos • 9 fans; Member since Aug 15, 2005

Favorites » His Blog

BBC NEWS | Education | Mathematicians set Chinese test: Apr 25, 2007 12:52pm 3 reviews •http://news.bbc.co.uk/2/hi/education/...; As is often in these questions, the image isn't a very accurate representation. If I'm correct, then the prism looks a bit like a kite, and is symmetrical along the plane A1AC, which pretty much proves i.

The answer to ii.) is the dot product of the normals of planes A1DB and DC1B (get the normals by taking the cross product of two normalized vectors in those planes, making sure you get the signs right). For question iii.), the answer is acos(dot(AD,(B-A)(c1-A)) or something like that.

Maybe I'm wrong, maybe not. There is no way I could have done this in my first year of secondary school and I've only got a clue how to do it as my job is programming graphics for 3D games -that's one thing the maths you learn in school (or don't learn, as the case may be; I learned all this stuff off my own back) is good for kids!

Ah, just re-read the page, this is for university entrance. Well, that's different. Whilst I'm not too hot at written exams, I would probably have fathomed out the method by age 16, having written a 3D modelling program by that age. Fear not blighty, some of us are edumacating ourselves!