with_slider(t,makelist(2-0.1*t,t,1,30),[x^2,-2*x-1,1+(t-1)*(x+1)],[x,-2,2.5],[y,-2,9]);

limit((abs(x+h)-abs(x))/h,h,0)

limit(((x+h)^n-x^n)/h,h,0)

limit((sin(x+h)-sin(x))/h,h,0)

limit((%e^(x+h)-%e^x)/h,h,0)

limit((log(x+h)-log(x))/h,h,0)

diff(log(x),x)