Answer:
B
Step-by-step explanation:
The double angle formulae for cosine is
cos2x = cos²x - sin²x
[ using sin²x + cos²x = 1 ]
cos2x = cos²x - (1 - cos²x) = cos²x - 1 + cos²x = 2cos²x - 1
Also cos2x = (1 - sin²x) - sin²x = 1 - sin²x - sin²x = 1 - 2sin²x
The double angle formulae are
cos2x = cos²x - sin²x = 2cos² - 1 = 1 - 2sin²x
Hence
cos60° = cos²30° - sin²30°
cos60° = 2cos²30° - 1
cos60° = 1 - 2sin²30°
B is not a representation of cos60°
Answer:
The equation 7(-1 1/2) = -10 1/2 means that the temperature change from 3 a.m. to 10 a.m. was -10 1/2 degrees
Step-by-step explanation:
Initially, the temperature was 3 1/2 degrees Fahrenheit at 3 a.m. From 3 a.m., the temperature change at 1 1/2 degrees per hour for the next 7 hours. This means that the temperature change in the next 7 hours is:
Temperature change = 7(-1 1/2) = -10 1/2
In the next 7 hours from 3 a.m. to 10 a.m., that is at 10 a.m. (3 a.m. + 7 hours), the temperature change was -10 1/2 degrees Fahrenheit.
Hence:
The equation 7(-1 1/2) = -10 1/2 means that the temperature change from 3 a.m. to 10 a.m. was -10 1/2 degrees
Answer:
A= 60
Step-by-step explanation:
1/2*12*10
60
There are 180 degrees in a triangle
4. 38+38= 76 degrees
180-76=104
Isosceles, Obtuse
5. 65+ x+x=65
Well we know one of the x
It is 90 degrees because it is a right angle
65+90=155
180-155=25
Scalene, Right triangle
6. 71+45= 116
180-116=64
7. Scalene, acute
8. 126+22=148
180-148=32
Scalene, Obtuse
9. 50+90=140
180-140=40
Right angle, Scalene
Please let me know if i got anything wrong
