第2个回答 2018-11-01
x= t-sint
dx/dt = 1-cost
y=1-cost
dy/dt = sint
dy/dx = (dy/dt)/(dx/dt) = sint/(1-cost)
dy/dx | t=π/2 = 1
x(π/2) = π/2 - sin(π/2) = π/2 -1
y(π/2) = 1- cos(π/2) = 1
切线方程 ( x(π/2), y(π/2) )
y-y(π/2) = dy/dx | t=π/2 . (x- x(π/2) )
y- 1 = (1) .( x- π/2+ 1)
x -y - π/2 - 2=0