The are used in different situations and not related. When you finally agree after some resistance at first to have dinner with that cool boy you give in, and you gave up your resistance. Giving in: agreeing with something after resisting first. Giving up: To stop something which is not finished. Like, you gave up school and dropped out. You gave up the marathon after 40Km

They both mean about the same thing but there can also be a slight difference in usage. Give up.. means to quit, surrender, relinquish Give in.. means to relent, to yield, capitulate Basically the same .. but.. Give up one's goals, on a question, on a riddle, in a fight, something that is treasured Give in to someone's demands, a debate, to temptation (like chocolate), For the most part, when somene begs or nags or presses strongly in an argument and the other person capitulates.. use "give in".

They mean the same thing. Giving up or giving in both mean to surrender.

You've received a lot of responses, and I support Azalea's answer to an extent, example sentences are the best way to understand the difference between the two. 「Give up」というのは諦めることだけの表現ですが、「Give in」というなら我慢できなかったし何かに酔わすぎたし、結果は諦めることです。それとも、何かやってしょうがないということもあります。もちろん母語としてこんな言葉を聞くと理解できるんですが、英語でも説明するのはけっこう難しいと思います。 I hope this helps.

There is usually a to after give in. Give in is intransitive. So,you can say: I won't give in, or I won't give in to your despotic power. Besides, give in means surrender or compromise. That's my humble opinion. Does it make any sense to you?