Suppose a curve is traced by the parametric equations

Question

x=1sin(t)
y=18-3cos^2(t)-4sin(t)
At what point (x,y) on this curve is the tangent line horizontal?

Answer 1

When dy/dx = (dy/dt)/(dx/dt) = 0

Do the calculation and first find the value of t. Use that co calculate x and y