8=4a+2b+c 0=a+b+c 0=4a-2b+c解為多少

8=4a+2b+c 0=a+b+c 0=4a-2b+c解為多少


a = 2
b = 2
c = -4



若10^m=2,10^n=3,10^(2m+3n)=
若3x+5y-4=0,則8^x*32^y=


若10^m=2,10^n=3,10^(2m+3n)=
解:10^(2m+3n)= 10^2m乘以10^3n
=(10^m)^2乘以(10^n)^3
=2^2乘以3^3
=4乘以27
=108
若3x+5y-4=0,則8^x*32^y=
解:8^x*32^y=(2^3)^x*(2^5)^y
=2^3x*2^5y
=(2)^3x+5y
=(2)^4
=16



求證1/n+1+1/n+2+…+1/3n+1>1(n屬於正整數)


用數學歸納法證明當n=1時左邊=1/2+1/3+1/4=13/12>1,成立假設n=k時成立即1/(k+1)+1/(k+2)+1/(k+3)…+1/(3k+1)>1當n=k+1時即要證明1/(k+2)+1/(k+3)+…+1/(3k+1)+1/(3k+2)+1/(3k+3)+1/(3k+4)>1式子裏比n=k的式子…