How to use scientific calculator to calculate sin20 ° 21 ′ 43 ″, sin20 ° 17 ′ 30 ″, sin19 ° 10 ′ 42 ″

How to use scientific calculator to calculate sin20 ° 21 ′ 43 ″, sin20 ° 17 ′ 30 ″, sin19 ° 10 ′ 42 ″

You can convert seconds and minutes to degrees, and the progress is 60,
Using a calculator: for example, using Casio's computer, if the sign sin is directly marked on the press key, first press sin and then press the number. If sin is marked on the top of the press key, then press shift and then press sin and then press the number. For example, if you know sin30 = 0.5, you can experiment

cos65-cos20+sin65-sin20=?

cos65-cos20+sin65-sin20
=cos(45+20)+sin(45+20)-cos20-sin20
=cos45 cos20 - sin45 sin20 + sin45 cos20 + cos45 sin20 - cos20 -sin20
=sqrt(2) cos20 -cos20 - sin20
Where sqrt (2) is the arithmetic square root of 2
It seems that this topic can only be reduced to this step

What is sin11 / 10 π * sin11 / 8 π * sin11 / 6 π of sin11 / π * sin11 / 3 π * sin11 / 5 π
Where * is the multiply sign / fraction~

sin(a)=sin(pi-a)
11/π-------11/10π
11/3π-------11/8π
11 / 5 π ------ 11 / 6 π so
The answer is 1