Preliminary mathematics marathon (1 Viewer)

[hscishard]

I only have Cambridge but I frequently borrow some textbooks from the library.

Lol my stupid year 10 self thought that Excel Ext 2 book contained all the Topics for 4unit, 3unit and 2unit. Wasted so much $$

 

[ohexploitable]

God. Wtf you used 4-unit differentiation. Obviously thats not 3 unit prelim.

You sure? It was just slightly different because implicit differentiation was required, after that it was just product rule.

 

[ohexploitable]

Please say how long your working out was.

No working out, I just drew the triangle and used a calculator to do sine rule

Anyone know where to find more of these contruction questions?

A tree stands at the north bank of a river with straight parallel banks running east to west. The angle of elevation to the top of a tree is 28° when measured from point A on the south bank and distant 3 metres to the west of the tree. From another point B on the south bank and distant 5 metres to the east of the tree, the angle of elevation of the tree is 19°. From a point half-way between A and B, find the angle of elevation of the top of the tree.

 

[hscishard]

You sure? It was just slightly different because implicit differentiation was required, after that it was just product rule.

Well..4unit is 4unit. Lol

 

[hscishard]

No working out, I just visualised the triangle in my head and used a calculator to do sine rule



A tree stands at the north bank of a river with straight parallel banks running east to west. The angle of elevation to the top of a tree is 28° when measured from point A on the south bank and distant 3 metres to the west of the tree. From another point B on the south bank and distant 5 metres to the east of the tree, the angle of elevation of the tree is 19°. From a point half-way between A and B, find the angle of elevation of the top of the tree.

Don't get the question. Is this 3d Trig?

 

[ohexploitable]

Here's a diagram:

The question asks you to find the angle of elevation of the tree from the midpoint of AB.

 

[ohexploitable]

Were are all the 2011ers?

 

[hscishard]

Is that 3d or 2d?

I still can't see how it works.

 

[ohexploitable]

It's in 3D, the two horizontal lines are the parallel river banks, the line going upwards is the tree.

 

[AAEldar]

Is that 3d or 2d?

I still can't see how it works.

I can see how it works, but we've just started Trig so I don't think I can do it :\

 

[hscishard]

What chap. is 3D trig in the Cambridge book?

 

[ohexploitable]

I don't think there is 3D trig in Cambridge.

 

[hscishard]

OMG.

Can you tell me how to do it please?

 

[hscishard]

No wait there is in Chp2 in the Year 12 3unit one.

 

[ohexploitable]

lol I never actually did the question, seems trippy.

 

[ohexploitable]

Oh wait, read the question wrong, it says find the angle of elevation of the tree from the south bank due south of the tree between A and B.

 

[hscishard]

lol I never actually did the question, seems trippy.

:mad1:...

Tell me!

 

[ohexploitable]

Yay! Solved it

 

[hscishard]

Yay! Solved it

Wha? Whered the 90 come from?
Wtf..how is that the mindpoint.

I like the minus part

 

[ohexploitable]

Wha? Whered the 90 come from?
Wtf..how is that the mindpoint.

I like the minus part

Oh wait, read the question wrong, it says find the angle of elevation of the tree from the south bank due south of the tree between A and B.

Haha yeah the minus, I was like how the fuck can they relate? And then I realised w was common.