When I was about 12 years old， I really wanted a new bike！ I 1 my parents my birthday wish，but I knew there was little hope because my family could 2 have that money.
On my birthday my parents told me they had my 3 outside in the back yard. At once I 4 out to the yard. There was my bike， 5 it wasn’t the bike that I thought it would be. This one was pink， old and worn with age. It was so 6！ I thought I 7 my parents’ feelings because I could see the disappointment 8 their faces and I was sure they could see it on mine. I 9 the old bike and rode it， feeling 10 that I had made my parents feel this way. So I put on a smile， rode as fast as I could and didn’t 11.
As time went by， I began to understand my parents gave me 12 much more than just a rusty（生锈的）old bike. They gave me a life lesson about 13. When you give something out of love， it doesn’t matter what it is in fact. What matters is the love that is in it. I like to remember this 14 because giving a gift is not about money. It’s about how much love you can feel from it. Do remember， a gift that 15 two dollars isn’t any less valuable（有价值的）than one that costs one hundred dollars， or even more.

①f（ $\frac{82}{3}$ π）=﹣ $\frac{\sqrt{3}}{4}$ ；

②若|f（x₁）|=|f（x₂）|，则x₁=x₂+kπ（k∈Z）；

③f（x）在区间﹣ $\frac{\pi }{4}$ ， $\frac{\pi }{4}$ 上单调递增；

④函数f（x）的周期为π．

⑤f（x）的图象关于点（ $\frac{\pi }{2}$ ，0）成中心对称．

其中正确说法的序号是____．

一个数除以15，商和余数都是14，这个数是____。