3(x - y)µÄ¶þ´Î·½ÔõÑùÈ¥À¨ºÅ

3(x-y) =3(x-2xy+y) =3x-6xy+3y


x - yÀ¨ºÅµÄƽ·½ÊÇʲô?

x-yÀ¨ºÅµÄƽ·½ÊÇx^2+y^2-2xy¡£¼ÆËã¹ý³Ì£º£¨x-y£©^2 =£¨x-y£©£¨x-y£©=x^2-xy-xy+y^2 =x^2+y^2-2xy ÇóÒ»¸öÊýµÄ¶þ´Î·½Ò²...


...´úÊýʽÀ¨ºÅXÈý´Î·½Y¼ÓXYÈý´Î·½.³ýÒÔÀ¨ºÅ¸ºXY

(x³y+xy³)¡Â(-xy)=xy(x²+y²)¡Â(-xy)=-(x²+y²)=-[(x+Y)²-2xy]=-[(-3)²-2¡Á3/2]=-6


²»È¥À¨ºÅ,°Ñx - y¿´×öÒ»¸öÕûÌåºÏ²¢:3(x - y) - 7(x - y)+2(y - x...

½â´ð:½â:ԭʽ=3(x-y)-7(x-y)-2(x-y)=-6(x-y).¹Ê´ð°¸Îª:-6(x-y)


3¡ÁÀ¨ºÅx - yÀ¨ºÅµÄƽ·½µÈÓÚʲô

3¡ÁÀ¨ºÅx-yÀ¨ºÅµÄƽ·½ =3*(x²-2xy+y²)=3x²-6xy+3y²


µÈʽ|x - y|= (x+y) 2 +() ÖеÄÀ¨ºÅÓ¦ÌîÈë - - - .

|x-y|= (x-y ) 2 = (x+ y) 2 -4xy .¹Ê´ð°¸Îª-4xy.


À¨ºÅx - yµÄÁ¢·½ºÍÀ¨ºÅy - xÁ¢·½ÊÇÒ»ÑùÂð?

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À¨ºÅ¸ºX¼õyÀ¨ºÅµÄÈý´Î·½³ýÒÔÀ¨ºÅx¼ÓyÀ¨ºÅµÄƽ·½

f'(x)=2x y'=-3x^2 ´¹Ö±ÔòбÂÊÊǸºµ¹Êý ËØ2x*(-3x^2)=-1 x^3=1/6 x=1/6^(1/3)ËùÒÔx0=1/6^(1/3)413154861335641


...À¨ºÅ´íÁË¡£Ó¦¸ÃÊÇÕâÑù°É¡£2/3x - (2/x+y)(x+y/3x - x - y...

(1)[1/(m+n)^2-1/(m-n)^2]¡Â[1/(m+n)-1/(m-n)]=1/(m+n)+1/(m-n)=2m/(m^2-n^2)µÚ(2)СÌâÎÒ¿´²»Ì«¶®,ÄãÔÙ¿´¿´ÄãÊÇ·ñ´ò´íÁË.


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