对于有理数a b,定义a b=3a-2b
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4*3=(4-3)/(4x3)=1/125*(1/12)=(5-1/12)/(5x1/12)=59/5
4※3=(4-3)/(4×3)=1/125※1/12=(5-1/12)÷(5×1/12)=(60-1)/5=59/5
3△(4△5)=3△[(4-5)÷(4×5)]=3△(-1/20)=(3+1/20)÷(-3×1/20)=61/20÷(-3/20)=-61/3
a*b=1/(a+1)(b+2)所以:a*(a+1)=1/(a+1)(a+1+2)=1/(a+1)(a+3)=(1/(a+1)-1/(a+3))/2.所以:1*2+3*4+5*6+.+2003*200
(-5)()(-4)()(-3)=(-5)*(-4)+1()(-3)=21()(-3)=21*(-3)+1=-63+1=-62
3*(-4)=3×(-4)/[3-(-4)]=-12/7
(-5)※(-4)※(-3)=[﹙-5﹚×﹙-4﹚+﹙-5﹚]※(-3)=15※(-3)=15×﹙-3﹚+15=-30
(—3)*(+2)=﹙-3﹚×2+﹙-3﹚+1=-6﹣3+1=﹣8
将a=3,b=-2代入定义式中得3⊙(-2)=[3-2×﹙-2﹚]÷[3×﹙-2﹚]=-7/6
7△(-6)=(3*7-6)/(7+3*6)=15/25=3/5
2*3=6/2+3=6/5(-3)*(-4)=12/(-3)+(-4)=-12/7再问:对于有理数ab,定义运算"*"如下a*b=ab/a+b,求2*3和(-3)*(-4)的值再答:2*3=6/(2+
-12-3+4=-11
4◆(-2)=-8-4-2-2=-16(-2)◆4=-8+2+4-2=-4所以4◆(-2)__<__(-2)◆4不满足交换律比如上面的4◆(-2)__≠__(-2)◆4
解∵a※b=(a-2b)÷(ab).∴3※(-2)=[3-2×(-2)]÷[3×(-2)]=(3+4)÷(-6)=-7/6
(-3)☆2=-3×2+22=-6+4=-2.故答案为:-2.
(-2)⊙3=(-2)×3-(2)-3-2=-6+2-3-2=-9
因为a*b=ab-b,所以(-3)*4=(-3)×4-4=12-4=8