初中数学知识点归纳总结精华版

零π7,23，。314ab2313ab235abc是6321axb0xax1把1把1’1实数a与baaaaaaa（aa02aaa-a（aa0aaaa33a1a10nab0ab,ab0ab,ab0ababaa1a;1a;1a;bbabab。a2bab。2y点xy0点xy0点xy0点xy0点xy0点yx0点xyP点x与y相等点x与yxyx点Px点Py点P点xy2y2yxxx1x,x,,x,xx12n122s[()()()xx21xx22xx2]snn1s[(xx)(xx)(xx)]222212nn11[(xxx)nx2]s[(xxx)]x2s221222221222nnnn1[(x'x'x')nx'2]s221222nn均数接近的常数a，得到一组新数据，x'xax'xa，…，x'xa，那么，1122nn1[(x'x'x')]x'2s221222nn,x,,x,x'xax'xax'xa，x12n1122nn',x',,x',x12n1xx)(xx)(xx)]ss222212nnb2A，底角为∠B、∠C，则∠2∠B，∠B=∠180A2xxxyyy•aa(m,n都是正整数)（a）a(m,n都是正整数)amnmnmn(ab)ab(n都是正整数)(ab)(ab)ab2nnn2(ab)a2abb(ab)a2abb222222amaa(m,n都是正整数,a0)nmn1a0a0);a(a为正整数)papabacabc)a2b(ab)(ab)a2abb(ab)a2abb(ab)2222222acadbcbda(cd)b(cd)(ab)(cd)a2(pq)apq(ap)(aq)分式AABBBacacacadadaaababac;cbdn;;()(nnbdbdbdbcbcbbccna(a0)a(a)2a(a0)a(a0)a2aa(a0)aba(0)ababa•b(a0,b0)b12D为ca22bc2•22•2•••A11222320123222100331333103sinAcosA1•22sinAcosAa2bc22ababbababsinA,cosA,tanA,cotA;sinB,cosB,tanB,cotBccbacca(n2)•n(n。21SCDAB)•DE2梯形ABCD①S③SSSSS；函数b0），那么y叫做x的yyb中的b为0时，yx的随x随x(xa)bxa是bb0xab，2xaba222abb(ab)2，把公式中的axx2bxb(xb)。22bb42bxc0(a0)xb40)ax222a即b24ac。即xxbxxc。，12a12axb2ayaxbxc(a,b,c是常数，a0)2ya(xh)k(a,h,k是常数，a0)2yaxbxc与xax2c02x和x12ax2bxca(xx)(xx)yaxbxc212ya(xx)(xx)124b2b当xbxxx1y是2a4a2a2b4b24axxxy2a12xxx随xxx122yaxbxc22xxyaxbxc随x21最大21最小1xxyaxbxcxxyaxbxc。21221最大12最小2yaxbxc(a,b,c是常数，a0)2yy0x0xbbbb，，2a2a2a2a4b24a4b24abb时，y随x随x2a2a的增大而减小；在对称轴的右侧，即当bb2a随x2a随xbb2a2a4b24a4b2yy4aax2bxc(a,b,c是常数，a0)a、b、cyaabab2accy）当xxxAB）21122则xxyy21212圆PO点P点P在⊙O上；点P在⊙O外。OllllR和d>R+r；两圆外切d=R+r；两圆相交