问一道初一完全平方公式的题如果答得好 最后加100悬赏分题目见下图：答案最好也是以图片的形式 展现出来 方便看
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问一道初一完全平方公式的题如果答得好 最后加100悬赏分题目见下图：答案最好也是以图片的形式 展现出来 方便看
问一道初一完全平方公式的题
如果答得好 最后加100悬赏分
题目见下图：
答案最好也是以图片的形式 展现出来 方便看
问一道初一完全平方公式的题如果答得好 最后加100悬赏分题目见下图：答案最好也是以图片的形式 展现出来 方便看
(1)X^2+1/X^2=(X+1/X)^2-(2)=(X-1/X)^2+(2)
(2)若a+1/a=5,则a^2+1/a^2的值是多少?
则：a^2+1/a^2=(a+1/a)^2-2=5^2-2=23
(3)若a^2-3a+1=0,则a^2+1/a^2的值是多少?
a1=3/2+(9/4-1)^0.5=3/2+(5/4)^0.5=3/2+5^0.5/2=(3+5^0.5)/2
a+1/a=(3+5^0.5)/2+1/((3+5^0.5)/2)
=(3+5^0.5)/2+2/(3+5^0.5)
=((3+5^0.5)^2+4)/(2*(3+5^0.5))
=(9+6*(5^0.5)+5+4)/(6+2*(5^0.5))
=(18+6*(5^0.5))/(6+2*(5^0.5))
=(9+3*(5^0.5))/(3+(5^0.5))
=3*(3+(5^0.5))/(3+(5^0.5))
=3
a^2+1/a^2=(a+1/a)^2-2
=3^2-2
=7
a2=3/2-(9/4-1)^0.5=3/2-(5/4)^0.5=3/2-5^0.5/2=(3-5^0.5)/2
a+1/a=(3-5^0.5)/2+1/((3-5^0.5)/2)
=(3-5^0.5)/2+2/(3-5^0.5)
=((3-5^0.5)^2+4)/(2*(3-5^0.5))
=(9-6*(5^0.5)+5+4)/(6-2*(5^0.5))
=(18-6*(5^0.5))/(6-2*(5^0.5))
=6*(3-(5^0.5))/2*(3-(5^0.5))
=6*(3-(5^0.5))/2*(3-(5^0.5))
=3
a^2+1/a^2=(a+1/a)^2-2
=3^2-2
=7