Diketahui y= 3x2-2 dan x= 1/4t-1 nilai dy/dt untuk t=1 adalah

x = 1/4 t -1
y = 3x^2 - 2 = 3(1/4 t - 1)^2 - 2
= 3(1/16 t^2 - 1/2 t + 1) - 2
= 3/16 t^2 - 3/2 t + 3 - 2
= 3/16 t^2 - 3/2 t + 1
dy/dt = d/dt ( 3/16 t^2 - 3/2 t + 1 )
= 6/16 t - 3/2
= 3/8 t - 3/2

saat t=1
3/8 t - 3/2 = 3/8 - 3/2 = -9/8