Different countries have different food, such as French fries, Italian pizza and so on. In China, fast food is becoming more and more popular these days. For example, McDonald's and KFC. Why do Chinese people like fast food so much? There are many reasons. First, it is quick. It takes little time. Second, it is easy to carry. Third, people like the restaurant's relaxing environment and American style. Though it tastes good, fast food generally contains little nutrition (营养). If you want to have a healthy body, do not go to fast food restaurants too often. Eat more fruit and vegetables.

①已知a，b，m都是正数，并且a＜b，则 $\frac{a+m}{b+m}$ ＞ $\frac{a}{b}$ ；

②在△ABC中，角A，B，C的对边分别为a，b，c，若∠A=60°，a=7，b=8，则三角形有一解；

③若函数f（x）= $\frac{4^x}{4^x+2}$ ，则f（ $\frac{1}{11}$ ）+f（ $\frac{2}{11}$ ）+f（ $\frac{3}{11}$ ）+…+f（ $\frac{10}{11}$ ）=5；

④在等比数列{a_n}中，a₁+a₂+…+a_n= $\frac{a_1\left(1-q^n\right)}{1-q}$ （其中n∈N^*，q为公比）；

⑤如图，在正方体ABCD﹣A₁B₁C₁D₁中，点M，N分别是CD，CC₁的中点，则异面直线A₁M与DN所成角的大小是90°．

其中真命题有____（写出所有真命题的序号）．