One time at a calculus lecture, my professor was warning us about simple mistakes costing us marks on an upcoming exam.

He told us of one instance where a student was faced with the equation (sin x)/x.

For those of you who are rusty with calculus, or haven't studied, you have to calculate the sine of x (where x is a number) before dividing it by x.

But that was lost on this student, who, apparently, crossed out the x's and left his answer as "sin". That's right. SIN.

We all had a hearty laugh about it when the professor proclaimed "and it's a SIN!"

What do you think? Is it a mortal sin, or venial sin?