Выпишите инфинитив из предложения, обусловьте его функцию, переведите предложения на российский

Выпишите инфинитив из предложения, определите его функцию, переведите предложения на российский язык.

1. We have discussed the terms to be included in the letter of credit to be opened by the buyer in favour of the seller.
2. One of the problems scientists are working at is to transmit energy to space stations by using lasers.
3. То develop a new submersible craft with a manipulator is not an easy task.
4. To conduct physical experiments with laser beams Russian physicists have developed large laser installations.