a:1:{i:0;a:13:{s:2:"id";s:3:"551";s:7:"answer1";s:177:"<p><img class="latex" src="https://chart.googleapis.com/chart?cht=tx&amp;chf=a,s,000000|bg,s,FFFFFF00&amp;chl=a_n%3D%5Cfrac%7B1-n%7D%7Bn%2B1%7D" alt="a_n=\frac{1-n}{n+1}" /></p>";s:7:"answer2";s:185:"<p><img class="latex" src="https://chart.googleapis.com/chart?cht=tx&amp;chf=a,s,000000|bg,s,FFFFFF00&amp;chl=b_n%3D%5Cfrac%7B(-1)%5En%7D%7Bn%2B1%7D" alt="b_n=\frac{(-1)^n}{n+1}" /></p>";s:7:"answer3";s:187:"<p><img class="latex" src="https://chart.googleapis.com/chart?cht=tx&amp;chf=a,s,000000|bg,s,FFFFFF00&amp;chl=c_n%3D%5Cfrac%7B(-1)%5Enn%7D%7Bn%2B1%7D" alt="c_n=\frac{(-1)^nn}{n+1}" /></p>";s:7:"answer4";s:175:"<p><img class="latex" src="https://chart.googleapis.com/chart?cht=tx&amp;chf=a,s,000000|bg,s,FFFFFF00&amp;chl=d_n%3D%5Cfrac%7B-2%7D%7Bn%2B1%7D" alt="d_n=\frac{-2}{n+1}" /></p>";s:7:"answer5";s:0:"";s:7:"answer6";s:0:"";s:7:"answer7";s:0:"";s:7:"answer8";s:0:"";s:7:"answer9";s:0:"";s:8:"answer10";s:0:"";s:4:"good";s:10:"0010000000";s:8:"question";s:4:"1811";}}