Slide t from left to right.[br]a) In what interval the slope of the tangent line is positive?[br]b) In what interval the slope of the tangent line is negative?[br]c) What is the value of t that the slope of the tangent line is 0?[br]d) What is the value of t that the slope of the tangent line does not exist?[br]Verify the answer of a, b, c and d with the value of [math]\frac{\frac{dy}{dt}}{\frac{dx}{dt}}[/math] at t in part a, b, c, d.[br]