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# Decide tan v if sin v = 1/√3 and if π/2 < v < π

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Decide tan v if sin v = 1/√3 and if π/2 < v < π

I've started of by deciding cos v by using this formula: sin2x + cos2x = 1 and got +- 2/√3, I don't know what to do next.

Guest Sep 2, 2018
#1
+93894
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sin v = 1/√3 and if π/2 < v < π       find tan v

It is in the second quadrant so tan will be negative.

Now I can just 'pretend' it is in the first quadrant for  all the working and then just add the minus sign at the end.

$$sin\; v=\frac{1}{\sqrt3}=\frac{opp}{hyp}\\ \text{Using pythagoras, the adjacent side must be }\sqrt{3-1}=\sqrt2\\ so\\ tan\;v=-\frac{opp}{adj}=-\frac{1}{\sqrt2}$$

Here is a represention of it on a number plane.

Melody  Sep 2, 2018
#2
+93894
+1

I know I have not done it your method. I always do them like this.

I think Heureka does it your way. I don't know about other people.

My way is easy though. ..

Melody  Sep 2, 2018
#3
+2

Aha i see, Thanks for your help

Guest Sep 2, 2018