应用数学公式解题时,不仅要学会直接应用,还应学会根据问题的需要,将公式加以变形而活用.下面通过例题来学习这种方法.一、完全平方公式的活用完全平方公式经过适当移项后得a2+b2=(a+b)2-2ab.例1已知a、b为方程x2-3x+1=0的两根,求a2+b2的值.解:由韦达定理得a+b=3,ab=1,所以a2+b When applying mathematics formulas to solving problems, not only must you learn to apply them directly, but you should also learn how to use the formulas to transform them according to the needs of the problem. Here is an example to learn how to use this method. First, the full square method of the complete squared formula is properly shifted. After the term, a2+b2=(a+b)2-2ab. Example 1 It is known that a and b are two equations x2-3x+1=0, find the value of a2+b2. Solution: obtained by Veeda theorem a+b=3, ab=1, so a2+b