由A和B进行均相二级不可逆反应<img src="https://nimg.ppkao.com/2019-05/tangling/2019051717064363030.jpg?sign=3b8cc34e4c62211718b7527444947104&t=62d720fc" />，速率方程：<img src="https://nimg.ppkao.com/2019-05/tangling/2019051717065843173.jpg?sign=02c6e86c343948addfd716f99f61387d&t=62d720fc" /> 求当<img src="https://nimg.ppkao.com/2019-05/tangling/2019051717105355873.jpg?sign=d665d50b679a1baa4c2d5d1bd0a597b5&t=62d720fc" />时的积分式。