There is a thermometer whose mercury surface is at 38 degrees Celsius. Xiaoming measured the temperature of the sick students without throwing it away. The result is There is a thermometer whose mercury surface is at 38 ℃. Xiao Ming measured the body temperature of the sick students without shaking. The results showed that the first time was 39.5 ℃, the second time was 39.5 ℃, and the third time was 39 ℃ A only the first time is right B only the third time is incorrect C is correct only for the third time The third time must be right, and the first time may be right Please give reasons

There is a thermometer whose mercury surface is at 38 degrees Celsius. Xiaoming measured the temperature of the sick students without throwing it away. The result is There is a thermometer whose mercury surface is at 38 ℃. Xiao Ming measured the body temperature of the sick students without shaking. The results showed that the first time was 39.5 ℃, the second time was 39.5 ℃, and the third time was 39 ℃ A only the first time is right B only the third time is incorrect C is correct only for the third time The third time must be right, and the first time may be right Please give reasons

Choose a
The original thermometer reading was 38 ℃, the first measurement was 39.5 ℃, higher than 38 ℃, which was accurate
Because the thermometer was not thrown, even if the thermometer was not measured in the future, it would still be 39.5 ℃, so the second and third times were not correct, BCD was wrong,
Especially the third time, the readings were wrong

Sin19 π / 9, sin19 π / 8 compare size
19 19
sin----π sin----π
9 8
Compare size

The solution sin19 π / 9 = sin (2 π + π / 9) = sin (π / 9)
sin19π/8=sin（2π+3π/8）=sin（3π/8）
From 0 ＜ π / 9 ＜ 3 π / 8 ＜ π / 2
So sin π / 9 is less than sin 3 π / 8
So sin19 π / 9 < sin19 π / 8

How do scientific calculators change the number of decimals in sin15 into fractions?

You need a slightly better calculator to have this function. ~ Casio fx-82es plus will do. There's a S &; D, click this