limit x->0 sin(x)/x
Let's evaluate the limit of sin(x)x when x0
The limit of sin(x) is 0 when x0
For sin(x)x, we encounter the indeterminate form 0/0 as x tends to 0
Let's apply L'Hôpital's rule (limit of a/b = limit of a'/b') by differentiating numerator and denominator:
Let's perform the differentiation: (sin(x))'
cos(x)
Let's perform the differentiation: (x)'
1
Using those derivatives, we obtain a new fraction whose limit can be computed:
The limit of cos(x) is 1 when x0
So the limit of sin(x)x is 1 when x0
Result:   1