log9 12=a,12^b=5,用a,b表示log45 24
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log9 12=a,12^b=5,用a,b表示log45 24
a=lg12/lg9
=(2lg2+lg3)/2lg3
2alg3=2lg2+lg3
lg3=2lg2/(2a-1)
b=lg5/lg12
=(1-lg2)/(2lg2+lg3)
2blg2+blg3=1-lg2
lg3=(1-lg2+2blg2)/b
2lg2/(2a-1)=(1-lg2+2blg2)/b
2blg2=2a-1+(2a-1)(2b-1)lg2
lg2=(1-2a)/(4ab-2a-4b+1)
lg3=-2/(4ab-2a-4b+1)
log45(24)
=lg24/lg45
=(3lg2+lg3)/(2lg3+1-lg2)
=(5-6a)/(4ab-4b-4)
=(2lg2+lg3)/2lg3
2alg3=2lg2+lg3
lg3=2lg2/(2a-1)
b=lg5/lg12
=(1-lg2)/(2lg2+lg3)
2blg2+blg3=1-lg2
lg3=(1-lg2+2blg2)/b
2lg2/(2a-1)=(1-lg2+2blg2)/b
2blg2=2a-1+(2a-1)(2b-1)lg2
lg2=(1-2a)/(4ab-2a-4b+1)
lg3=-2/(4ab-2a-4b+1)
log45(24)
=lg24/lg45
=(3lg2+lg3)/(2lg3+1-lg2)
=(5-6a)/(4ab-4b-4)
log9 12=a,12^b=5,用a,b表示log45 24
已知log18 5=a 18^b=3 用a b表示log45 12
已知log18(5)=a ,18^b=3 用a与b表示log45(12)
log9 5=a,log3 7=b试用a,b表示log21 35
已知log9 5=a,log3 7=b,试用a,b表示log35 9的值(用a,b表示)
已知log9 5=a,log9 7=b,求log35 9的值
已知log18^9=a,18^b=5.求log45的值.
设9^a=45.log9(5)=b 则a与b的关系
log9的5次=a,log9的7次=b,求log35的9次,
log9的五次=A log9的七次=B log3的35次?
利用对数运算性质解题log9^2=a,(1/3)^b=5,用a,b表示log3^120 (即以3为底120的对数)
log9^5=a,log3^7=b,求log35^9=?