have a look意思是一般用于建议别人。take a look 一般是表达自己的想法…比如买东西时人家问你 Can I help you?你就要回答 Just take a look（随便看看）。
take a look和have a look的区别
首先take是正式,have多随意.所以take a look at 有检查之意,较为严肃,have a look at就是去看看,比较口语和生活化.take a look in 后可以接地点,比如Because I bought the ticket which I could take a look in the palace.但是at后面接具体的事情或者抽象的东西,比如Have a look at what happens.
take的用法
1.表示“拿去”“带去”等，与 bring(拿来)方向相反。如：
Please take the empty cup away and bring me a cup of tea. 请把这个空杯拿走，给我倒杯茶来。
若语义需要，其后可带双宾语;若双宾语易位，用介词to引出间接宾语。如：
Please take him a cup of tea.=Please take a cup of tea to him. 请给他端杯茶去。
有时表示“拿去”可能与方向无关。如：
He took the box to the farm. 他把那个箱子带到了农场。
2.表示“搭乘(交通工具)”，比较下面的同义表达：
他决定乘出租车去火车站。
正：He decided to take a taxi to the railway station.
正：He decided to go to the railway station by taxi.