化简:lg5lg20-lg2lg50-lg25=______.
题型:填空题难度:一般来源:不详
化简:lg5lg20-lg2lg50-lg25=______. |
答案
由题,lg5lg20-lg2lg50-lg25 =lg5(2lg2+lg5)-lg2(2lg5+lg2)-2lg5 =lg25-lg22-2lg5 =lg5-lg2-2lg5 =-(lg2+lg5) =-1 故答案为-1 |
举一反三
(1)计算:log3+lg25+lg4+7log72+(-9.8)°
(2)化简:sin(π-α)cos(π+α)cos(π+α) | cos(3π-α)sin(3π+α)sin(π-α) | . |
已知两变量x,y满足lg(x+y)=lgx+lgy,则实数y的取值范围为______. |
计算:lg25+2lg2+eln2+log3=______. |
计算 (log29)•(log34)=______. |
函数f(x)=(log2x+1)(log2x-5),x∈[1,16],则f(x)的值域为______. |
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