已知log14 7=a,log14 5=b,求log35 28(用a,b表示)log 14 7 = lg 7 / lg 14 log 14 5 = lg 5 / lg 14 A = lg 7 / lg 14 = lg 7 / (lg 7 + lg 2) B = lg 5 / lg 14 = (1 - lg2) / (lg 7 + lg 2) 通过以上两式可得:lg 7 = A / (1 - A + B) lg 2 = (1 - A) / (
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![已知log14 7=a,log14 5=b,求log35 28(用a,b表示)log 14 7 = lg 7 / lg 14 log 14 5 = lg 5 / lg 14 A = lg 7 / lg 14 = lg 7 / (lg 7 + lg 2) B = lg 5 / lg 14 = (1 - lg2) / (lg 7 + lg 2) 通过以上两式可得:lg 7 = A / (1 - A + B) lg 2 = (1 - A) / (](/uploads/image/z/12572188-52-8.jpg?t=%E5%B7%B2%E7%9F%A5log14+7%3Da%2Clog14+5%3Db%2C%E6%B1%82log35+28%28%E7%94%A8a%2Cb%E8%A1%A8%E7%A4%BA%29log+14+7+%3D+lg+7+%2F+lg+14+log+14+5+%3D+lg+5+%2F+lg+14+A+%3D+lg+7+%2F+lg+14+%3D+lg+7+%2F+%28lg+7+%2B+lg+2%29+B+%3D+lg+5+%2F+lg+14+%3D+%281+-+lg2%29+%2F+%28lg+7+%2B+lg+2%29+%E9%80%9A%E8%BF%87%E4%BB%A5%E4%B8%8A%E4%B8%A4%E5%BC%8F%E5%8F%AF%E5%BE%97%3Alg+7+%3D+A+%2F+%281+-+A+%2B+B%29+lg+2+%3D+%281+-+A%29+%2F+%28)
已知log14 7=a,log14 5=b,求log35 28(用a,b表示)log 14 7 = lg 7 / lg 14 log 14 5 = lg 5 / lg 14 A = lg 7 / lg 14 = lg 7 / (lg 7 + lg 2) B = lg 5 / lg 14 = (1 - lg2) / (lg 7 + lg 2) 通过以上两式可得:lg 7 = A / (1 - A + B) lg 2 = (1 - A) / (
已知log14 7=a,log14 5=b,求log35 28(用a,b表示)
log 14 7 = lg 7 / lg 14
log 14 5 = lg 5 / lg 14
A = lg 7 / lg 14 = lg 7 / (lg 7 + lg 2)
B = lg 5 / lg 14 = (1 - lg2) / (lg 7 + lg 2)
通过以上两式可得:
lg 7 = A / (1 - A + B)
lg 2 = (1 - A) / (1 - A + B)
请问下 log7 和log2 是怎样用a b 表示的?
已知log14 7=a,log14 5=b,求log35 28(用a,b表示)log 14 7 = lg 7 / lg 14 log 14 5 = lg 5 / lg 14 A = lg 7 / lg 14 = lg 7 / (lg 7 + lg 2) B = lg 5 / lg 14 = (1 - lg2) / (lg 7 + lg 2) 通过以上两式可得:lg 7 = A / (1 - A + B) lg 2 = (1 - A) / (
不需要那样
log35(28)=log14(28)/log14(35)
log14(28)=log14(14)+log14(14)-log14(7)=2-a
log14(35)=log14(5)+log14(7)=a+b
log35(28)=(2-a)/(a+b)