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 dy x= sec t-1,y=tant;t= 4 Write the equation of the tangent line. y= X+ (Type exact answers, using radicals as needed.) What is the value of dy dx 2 at this point? dy dx2 = (Type an exact answer, using radicals as needed.) dx at this point.