题目

People are overweight for many reasons, the most important one of which is that they eat the wrong foods, get the wrong types of calories per meal, and they also eat meals at the wrong time each day. Food is more powerful than any weight loss pill, because the food that you eat can either make you thin or fat. This is true because your body is like an engine, and it only needs certain foods at certain intervals(间隔) each day. Low-calorie Diets Do Not Work The reason people cannot lose weight by starving themselves is that their metabolism(新陈代谢) will detect any major drop in c（本小题满分12分） 已知向量，，且. （1）求tanA的值； （2）求函数的值域.