"Yeah, sure."

all is summarized in your first answer :) i felt all your kindness at first, tnx for this wonderful examples, i like second offer is incridibly much ;) be happy with positive attitudes always :)

I hope that this is helpful. 

Yeah, sure! I will give you an example. Why not?  :)

A "Yeah, sure" can be a positive, Happy to do it, response for a request, or it could suggest a, Well, okay, I'll do it, but I really don't want to kind of attitude.  It all depends on your tone of voice and your attitude about doing something that some has asked you to do.                                                                                             

Ex. 1.  

A: “Will you help me with my homework?”

B: responding with a long winy voice--an attitude of feeling dragged into doing something that is not really a desired act:  “mmm, “Yeahhh, surrre, I don’t have anything better to do with my life at the moment.”

Ex, 2.

A:  “Hey! Would like some of my ice cream?”

B: responding with the excited voice of a little kid seeing his dad pull up into the front yard with a brand new pony, “Yeah sure!  I’d be tinkled-pink to share your ice cream with you.”

Again, it’s pretty much about attitude.

Note: if you choose to use this expression to show a happy willingness to do something for someone else—it would be best to express it with a happy voice when using “Yeah, sure” so that the person whom you are expressing it to understands fully that you are more than happy to do something that they have asked you to do.  

could you plz give me an example? or plz exemplify a situation in which "yeah, sure" can be used?