Tuesday, September 3, 2013

given tan(x)=1/square root of 3 and sec(x)

Given that tanx =
1/sqrt(3)


We need to find sinx and
cosx


We know that tanx = sinx
/cosx


==> sinx/cosx =
1/sqrt(3)


Cross
multiply:


==> cosx = sqrt(3)*
sinx...........(1)


Also, we know that sin^2 x + cos^2 x =
1...........(2)


We will substitute with (1) into
(2):


==> sin^2 x + [sqrt3*sinx]^2 =
1


==> sin^2 x + 3sin^2 x =
1


==> 4sin^2 x =
1


Divide by4.


==> sin^2
x = 1/4


==> sinx = +-
1/2


==> cosx = sqrt3
sinx


==> cosx = +- sqrt3 /
2


But given that secx < 0 ==> cosx <
0


==> cosx = -sqrt3
/2


==> sinx =
-1/2

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