fraction operator

1. type solve(x = 4$x, x) in any row
2. now Calctus lags with every keystrokes

solve(x = 4$x + 2$x, x) makes more lag. solve(x = 4/x, x) does not cause lag.

rand()

1. type solve(rand()+rand()+rand()+x = 5, x) in any row
2. now Calctus lags with every keystrokes

log2()

1. type solve(log2(x) = 10, x) in any row
2. Calctus hangs for some seconds
3. now Calctus lags with every keystrokes