Trig thing

[TonyHem]

There is a picture but since I haven't got a scanner, i'll try to describe it.

"A building is being constructed from pre-cast concrete slabs. A vertical wall panel is being supported by two metal struts which are anchored at the variable point A on the horizontal floor. The distance OB is 4 metres, the distance BC is 5 metres, the distance AO is x metres and the angle BAC is (theta) radians.

Use an apporpriate trigonometric identity to show that: Tan(theta) = 5x/(x^2+36)

Right angle triangle.
1. The corner of this triangle (at the very bottom), is point O. Going up 4 meters (directly up) is point B and 5 meters above point B is point C.
A line goes from point B to a point on the x-axis reaching point "A".This "a" point has another line connecting to point C.

[TrueTears]

Hm.. This question looks similar to one I've done, but I can't seem to visualise the picture(Like what point is O, B etc) haha, can you do a rough drawing of the diagram on paint and upload it on here?

[TonyHem]

The place I put "5", "4", "x", is like the distance from the points.

[TrueTears]

Let angle CAO (lol ) be

so angle BAO



now and also

sub this in yields:



Solving for yields

[TonyHem]

lol for some reason I kept on trying to move my theta and 2nd variable around :S
Thanks!

[Flaming_Arrow]

another way to do it is

and then solving for

[TrueTears]

another way to do it is

and then solving for

Yeap, just using the addition compound formula