Find an equation for the line tangent to the curve at the point defined by the given value of t. Also, find the value of \frac{d^2y}{dx^2} at this point
$x = \cos t$, $y = \sin t$, $t = \frac{\pi}{6}$
Write the equation of the tangent line
y = \boxed{}x + \boxed{}
(Type exact answers, using radicals as needed)
