3D Trig. (1 Viewer)

[NizDiz]

Probs my worst section in 3U (haven't learn't Perms/Comb. and Binomial yet). How is the best way to approach 3D trig questions?

 

[HeroicPandas]

Either improve ur spatial ability over time OR just look at EVERY single shape (esp. triangles) one by one

 

[iBibah]

Probs my worst section in 3U (haven't learn't Perms/Comb. and Binomial yet). How is the best way to approach 3D trig questions?

Maybe post a question as an example?

 

[NizDiz]

Question 13 a)??

 

[coyney]

Here is my solution, I think it is correct.
http://gyazo.com/b513f58e8a1b6b32627563c0a38e0820.png

 

[NizDiz]

I'm confused with angle PBQ, is it cos43 or cos47? how to determine?

 

[HeroicPandas]

I'm confused with angle PBQ, is it cos43 or cos47? how to determine?

"Q is South 47 East from B."

So if u've drawn the vertical and horizontal (north and south) axes for B, since the bearing of "Q is South 47 East from B.", the angle beginning from the vertical (south) axis ending at the line BQ is 47 degrees, hence angle(BPQ) = 90 - 47 = 43

 

[NizDiz]

yeh sweet, thanks

 

[rickster]

Make sure your diagram for any question in 3D trig is big, clear and correct. It seriously helps to take a minute just to draw it properly. Don't forget the tools you have at your disposal to find missing sides and angles: sine rule, cosine rule, trig ratios, simultaneous equations, Pythagoras theorem and trig identities. Above all, read the question properly.

 

[pheelx3]

A few tips which my tutor has told me:
- Always chase for tan (90% of the questions)
- Always look at the base triangle bc usually the q will involve that or you can use that to find "h" or whatever.