1: lim(x-->0) sin(sinx)/sinx...i have solved using l'hopitals rule to get 1

Mr F says: Correct. But no need for the Hospital. Just make the substitution . Note that as . is a standard result.
2: lim(x-->infinity) ln(x)/(x^2) i have got a value of 0

Mr F says: Correct.
3: The size of an animal’s pupils expand and contract depending on the amount of light available. Let

**f(x) = (160x^(-0.4)+90)/(8x^(-0.4)+10)**
be the size in mm of the pupils at light intensity x. Find

**lim(x-->0+)** and

**lim(x-->inf)** for f(x), and argue that these represent the largest and smallest possible sizes of the pupils

Can someone please check my answers for 1 and 2 and give me some help for question 3?

P.S sorry about the bad notation for the equation and limits