F.6 M2 about vectors~~~

圖片參考：http://imgcld.yimg.com/8/n/HA00265776/o/701109290113913873468590.jpg


In the figure, AC = 10. u and v are two unit vectors. The angles u and v make with vector AC are 25 and 40 respectively. Express vector AC in terms of u and v. (Give your answer correct to 1 demical place.)