check if...

Hi,

Could you please tell me what differences in meaning there are among "check if...," "check to see if..." and "see if..."?

check if + "subject" + "verb"
- I've attached a rough draft of next week's presentation. Please check if eveything is okay, and get it ready to submit.
- Could you go and check if the baby is asleep?

check to see if + "subject" + "verb"
- We executed a few other transactions yesterday. Can you check to see if the confirmations were sent?
- She checked to see if any pages were missing or illegible.
- First, I checked to see if the website was still accessible.

see if + "subject" + "verb"
- I want you to send me a brief on that company's background and history, so we can see if they are reliable business partners.
- See if this needs more salt.
- It's a very vibrant atomosphere. Let's see if we can talk to one of the demonstrators.

It seems to me that they all are interchangeable.

To vivemafille:
Thank you for the reply.

To everybody else:
Do you, too, think that those three are all interchangeable?

I agree. They are interchangable.

Check if = see if

Check if + see if = Check to see if

An alternative word to if is whether.

Can you please check/see/check to see whether the door is locked?

I'm not a qualified teacher.

Thank you very much, colloquium.

Is there anyone who sees any differences in meaning?