Help me with this derivative interpretation?

Question

The period, T, of a pendulum is given in terms of its length, l , by

T = 2phi(l/g)^1/2

If I find the sign of dT/dl is positive then what does this tell about the period of pendulums???

Need answer right away, thanks

Answer 1

It tells you that if you increase the length of the pendulum then the period will increase as well

Answer 2

It tells you that every T seconds later, the pedulum is at the same position as it was T seconds ealier.

Answer 3

nothing.it will show that the slope of the curve is positive