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The number of boys in class 62 is 4 / 5 of the number of girls. What is the percentage of boys in the class, what is the percentage of girls in the class, and what is the percentage of girls in boys?
The number of boys in class 6 and class 2 is 4 / 5 of the number of girls. The number of boys accounts for 4 / 9 of the whole class, the number of girls accounts for 5 / 9 of the whole class, and the number of girls is 5 / 4 of the number of boys
Sin75 ° = sin30 ° cos45 ° + cos30 ° sin45, why is it calculated like this? Is it a formula? That is to say, sin75 = sin (45 + 30) and then why does it become sin30 ° cos45 ° + cos30 ° sin45
There is a formula sin (α + β) = sin α cos β + cos α sin β 75 ° = 30 + 45, that is, sin 75 = sin (45 + 30) = sin 30 ° cos 45 ° + cos 30 ° sin 45
EN, according to the formula: sin (a + b)= sina.conb + cosa.sinb
Boys in class 62 account for two-thirds of the class. What is the proportion of girls to boys?
Girls make up one-third of the class and one-half of the boys
Sin140 degree cos20 degree cos140 degree cos70 degree simplified evaluation
Sin140, cos20, cos140, cos70
=Sin140 degrees cos20 degrees - cos140 degrees cos20 degrees
=Sin (140-20 degrees)
=Sin (120 degrees)
=√3/2
There were 42 students in class 62, four out of seven of whom were boys. Later, there were several girls. At this time, the ratio of boys to girls was six to five. How many students are there in the class now
Boys 42 × 4 / 7 = 24
At present, the proportion of male students in the whole class is 6 / 11 24 △ 6 / 11 = 44 (people)
Evaluation: cos20 ° / (cos70 ° - 2cos10 °)
Cos20 ° / (cos70 ° - 2cos10 °) = cos20 ° / (COS (60 ° + 10 °) - 2cos10 °) for the convenience of writing, first calculate the denominator as follows: (cos70 ° - 2cos10 °) = cos (60 ° + 10 °) - 2cos10 ° = cos (60 ° + 10 °) - 2cos10 ° = 1 / 2cos10 ° - √ 3 / 2sin10 ° - 2cos10 ° = - √ 3 (
zero point one seven six five four seven one four four
There are 23 boys and 25 girls in class 1. There are 42 students in class 6-2. How many percent more students are in class 6-1 than in class 6-2?
（23+25-42）/42=14.28%
What is sin22 ° sin23 ° - cos22 ° cos23 ° equal to?
-cos45º＝-√2╱2
sin(22°)*sin(23°)-cos(22°)*cos(23°) = -0.70710678118655
The root of two is two
The number of boys in class 6 (1) is three fifths of that of girls. The number of girls is a fraction of that of boys. What is the number of boys in the whole class
The number of male students in class 6 (1) is three fifths of that of female students, the number of female students is five thirds of that of male students, and the number of male students is three eighths of that of the whole class
Do not understand can ask, help please adopt, thank you!
Evaluate sin68 ° cos23 ° - cos68 ° sin23 °=
sin68°cos23°-cos68°sin23°
=sin（68°-23°）
=sin45°
=√2/2
sin（a-b）=sinacosb-cosasinb
Sin68 ° cos23 ° - cos68 ° sin23 ° = sin (68 ° - 23 °) = sin45 ° = radical 2 / 2
sin68°cos23°-cos68°sin23°
=sin(68°-23°)
=sin45°
=Root 2 / 2
sin68°cos23°-cos68°sin23°=sin(68°-23°)=sin45°=√2/2
Zero
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