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# Trigonmetry watch

1. See attachment for the diagram of the triangles. The 2 triangles are similar, and the first part of the question is to write down the length of the side marked x....this is 10.5cm

The next part of the question says, given that tanx= 3, what are the values of sinx and cos x respectively.
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3. huh
4. Are you sure it's and not
5. thats what i thought...but the sheet says tan x...
6. Considering they are not right angle you would have a pretty tough time getting a meaningful answer from tan(theta).
7. The sheet must be wrong. You can't have tan of a side. It has to be an angle.
8. (Original post by Nandoz)
See attachment for the diagram of the triangles. The 2 triangles are similar, and the first part of the question is to write down the length of the side marked x....this is 10.5cm

The next part of the question says, given that tanx= 3, what are the values of sinx and cos x respectively.
I think you mean 11.5.

Are the triangles right angled?

EDIT: 10.5
9. yeah the triangles are right angled...why is it 11.5 and not 10.5 btw?
10. (Original post by Nandoz)
yeah the triangles are right angled...why is it 11.5 and not 10.5 btw?
I am seriously hung over. . That's why.

If they are right angled, then what's your problem?
11. The reference to tan(x) is completely unrelated to the question.

Draw a triangle satisfying tanx = 3. i.e. a triangle with opposite three and adjacent 1.

Now work out the values of cosx and sinx using pythagoras's theroem.
12. hmmm i still don't get it
13. tan of an angle is defined to be the ratio between the opposite and adjacent.

If you had an angle, y, you could name sides relative to that angle.

Hyp for the longest, adj for the nearest and opp for the side furthest away.

As all triangle with a an angle y are similar, (right triangles), it follows that the ratio of the sides are always the same.

Therfore, tan is defined to be o/a, which means you draw a right triangle, and from your angle you put 3 for opposite and 1 for adjacent's length. You then work out the length of the hypotenuse using pythagoras.

Remember the definitions:

sin(x) = o/h cos(x) = a/h.
14. so does sin x = 3/3.16 and cos x = 1/3.16
15. yeah
16. (Original post by Nandoz)
so does sin x = 3/3.16 and cos x = 1/3.16
You can make them into slightly nicer fractions.

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Updated: November 9, 2008
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