求10^x-197y=1的最小解?
解:令10^x=10m,→10m-197y=1,→1/(197/10-20+1/3)=-30,m0/y0=-59/-3,
10*-59-197*-3=1,
→mn=-59+197t或138+197t,→10^x=10mn=10(197t-59)=10(197t+138)
建立方程(197t-59)|10^r=(197t+138)|10^r=0,且使r取最大值,→①有且只有t=a0T7符合,令a0=1~9,当a0=4时,r取最大值;→t=a1T47;令a1=1~9,当a1=4时,r取最大值(尾数0最多);同理得:a2=4,a3=6,…,a96=5,r取最大值(尾数0最多),且余数为1。即:(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096447-59)/10^97=1
或②有且只有t=a0T6符合,→(197*46+138)|10^2=0,…
(197*324873096446+138)|10^12=0,…(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096446+138)/10^97=1。
最后求得:
10^x=10(197t-59)=10(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096447-59)=10^98,→x=99。
或
10^x=10(197t+138)=10(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096446+138)=10^98,→x=99。
解:令10^x=10m,→10m-197y=1,→1/(197/10-20+1/3)=-30,m0/y0=-59/-3,
10*-59-197*-3=1,
→mn=-59+197t或138+197t,→10^x=10mn=10(197t-59)=10(197t+138)
建立方程(197t-59)|10^r=(197t+138)|10^r=0,且使r取最大值,→①有且只有t=a0T7符合,令a0=1~9,当a0=4时,r取最大值;→t=a1T47;令a1=1~9,当a1=4时,r取最大值(尾数0最多);同理得:a2=4,a3=6,…,a96=5,r取最大值(尾数0最多),且余数为1。即:(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096447-59)/10^97=1
或②有且只有t=a0T6符合,→(197*46+138)|10^2=0,…
(197*324873096446+138)|10^12=0,…(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096446+138)/10^97=1。
最后求得:
10^x=10(197t-59)=10(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096447-59)=10^98,→x=99。
或
10^x=10(197t+138)=10(197*50761421319796954314720812182741116751269035532994923857868020304568527918781725888324873096446+138)=10^98,→x=99。