9.99.9積的乘方積的乘方知識回顧知識回顧填空：填空：1.a1.amm+a+amm=_,=_,依據(jù)依據(jù)_._.2.a2.a3 3aa5 5=_ ,=_ ,依據(jù)依據(jù)_3.3.若若a amm=8,a=8,an n=30,=30,則則a am+nm+n=_.=_.依據(jù)依據(jù)_4.(a4.(a4 4)3 3=_,=_,依據(jù)依據(jù)_5.(m5.(m4 4)2 2+m+m5 5mm3 3=_,(a=_,(a3 3)5 5(a(a2 2)2 2=_.=_.2a2amm合并同類項法則合并同類項法則a a8 8同底數(shù)冪的乘法同底數(shù)冪的乘法240240a a1212冪的乘方冪的乘方2m2m8 8a a1919逆用同底數(shù)冪的乘法逆用同底數(shù)冪的乘法2公開課(1(12)2)4 4_;1_;14 42 24 4 =_;=_;3 3(-2)(-2)3 3_;3_;33 3(-2)(-2)3 3=_;=_;()()2 2 ;=;=1111232316161616216216216216你發(fā)現(xiàn)了什么你發(fā)現(xiàn)了什么?2222()()1111(2323136136填空：填空：3公開課(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))猜想猜想:你能說明理由嗎？你能說明理由嗎？=(ab)=(ab)(ab)(ab)(ab)(ab)n n個個abab =(a =(aa aa)a)(b(bb bb)b)n n個個a na n個個b b =a =an nb bn n(ab)(ab)n n(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n結論：結論：結論：結論：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))你能說明理由嗎？你能說明理由嗎？=(ab)=(ab)(ab)(ab)(ab)(ab)n n個個abab =(a =(aa aa)a)(b(bb bb)b)n n個個a na n個個b b =a =an nb bn n(ab)(ab)n n冪的意義冪的意義乘法的交換乘法的交換律、結合律律、結合律乘方的意義乘方的意義(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n積的乘方的運算性質：積的乘方的運算性質：結論：結論：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n你能用文字語言敘述這個性質嗎？你能用文字語言敘述這個性質嗎？積的乘方積的乘方,把積的每一個因式分別乘方把積的每一個因式分別乘方,再把所得的冪相乘再把所得的冪相乘.積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n 積的乘方積的乘方,把積的每一個因式分別乘方把積的每一個因式分別乘方,再把所得的冪相乘再把所得的冪相乘.例例1 1 計算：計算：(1)(1)（3a)3a)4 4 (2)(-2mx)(2)(-2mx)3 3(3)(-xy(3)(-xy2 2)3 3 (4)()(4)()2 2232xy1.1.計算：計算：(1)(1)(-ab)(-ab)5 5 (2)(x (2)(x2 2y y3 3)4 4(3)(2a(3)(2a3 3)2 2 (4)(-3a (4)(-3a3 3)3 32.2.下面的計算是否正確？如果有錯誤，請下面的計算是否正確？如果有錯誤，請改正改正.(1)(1)(xy(xy2 2)3 3=x y=x y6 6(2)(2)(-2b(-2b2 2)2 2=-4b=-4b4 4積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n請你推廣請你推廣:(abc)(abc)n n=a an nb bn nc cn n(n(n為正整數(shù)為正整數(shù))(abc)(abc)n n=(ab)(ab)ccn n=a=an nb bn nc cn n=(ab)(ab)n nc cn n1 1積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n(abc)(abc)n n=a an nb bn nc cn n(n(n為正整數(shù)為正整數(shù))請你推廣請你推廣:(abc)(abc)n n=(ab)(ab)ccn n=a=an nb bn nc cn n=(ab)(ab)n nc cn n積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n1 1(abc)(abc)n n=a an nb bn nc cn n(n(n為正整數(shù)為正整數(shù))積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n1 1(abc)(abc)n n=a an nb bn nc cn n(n(n為正整數(shù)為正整數(shù))例例2 2 計算：計算：(1)(1)（3xy3xy2 2)2 2(2)(-2ab(2)(-2ab3 3c c2 2)4 4例例3.3.計算：計算：(-a)(-a)3.3.(-a)(-a)4 4 3(x 3(x2 2y y2 2)-2(x)-2(x3 3y y3 3)2 2 (3a (3a3 3)2 2+(2a+(2a2 2)3 3 14公開課拓展訓練拓展訓練 的值求已知則則若則）若（m，xy，yxx，x，mnnmxbax327216286432222259639440313281（5）若n是正整數(shù)，且 ，求 的值。5,6nnyxnxy2你會計算你會計算 嗎？嗎？441()22逆用積的乘方逆用積的乘方的運算性質的運算性質積的乘方的運算性質：積的乘方的運算性質：(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))(ab)(ab)n n=_.(n=_.(n為正整數(shù)為正整數(shù))a an nb bn n1001001()22111222222()().()()().()6122()()=1=1111222222(.)(.)(.)(.)6 6個個126 6個個2 2解：原式解：原式解：原式解：原式66122()你會計算你會計算 嗎？嗎？4520 254.441144.().()4101424.().()計算計算:.()200820091333 410124()()4 逆用同底數(shù)冪的逆用同底數(shù)冪的乘法運算性質乘法運算性質逆用積的乘方逆用積的乘方的運算性質的運算性質45144()()441444()41444()()414 逆用冪的乘方逆用冪的乘方的運算性質的運算性質42 5124()()()()解：原式解：原式410124()()810122()()4 逆用同底數(shù)冪的逆用同底數(shù)冪的乘法運算性質乘法運算性質逆用積的乘方逆用積的乘方的運算性質的運算性質8821222()()821222()()逆用冪的乘方逆用冪的乘方的運算性質的運算性質冪的乘方的運冪的乘方的運算性質算性質2 410122()()解：原式解：原式