题已知a、b是不相等的正数，试求函数的最值．此题若用通常解法，不仅繁而且难，但如果能根据题目结构，引进适当的参数，给参数赋予几何含义，则将会显得明快和直观．解设，，则a2＋v2=a＋b．因为a、b为不相等的正数，可设ab．易得因此问题就转化为（如图）：在AMB上求点，使 Know that a, b are not equal positive numbers, try to find the value of the function. If this problem is solved by ordinary methods, it is not only tedious but also difficult. However, if you can introduce appropriate parameters according to the structure of the topic and give the parameters a geometric meaning, it will be clear and intuitive. Solution, then a2+v2=a+b. Since a and b are not equal positive numbers, ab can be set. Easy to get, so the problem is converted into (see figure):