题目

Dior was born in Normandy in 1905, and his family' s original plans for him included a career in the diplomatic service, but by the time he was twenty-three, with his parents' money, he opened a small art gallery in Paris. By 1931, the money had been used up. Dior' s friends in the art gallery, asked him to draw and he took his first step at designing and drawing. His first job was with Lucien Lelong from whom Dior learned his craft (手艺). In February,  1947,  Dior started the New Look in his first major Paris collection. He was backed by a famous textile producer, Boussac, who looked aft小虎同学在计算a+2cos60°时，因为粗心把“+”看成“-”，结果得2006，那么计算a+2cos60°的正确结果应为________．