Answer:
sin 15° = 0.2588
Step-by-step explanation:
The half angle formula is:
![\sin{(\frac{x}{2})} = \pm \sqrt{\frac{1 - \cos{x}}{2}}](https://tex.z-dn.net/?f=%5Csin%7B%28%5Cfrac%7Bx%7D%7B2%7D%29%7D%20%3D%20%5Cpm%20%5Csqrt%7B%5Cfrac%7B1%20-%20%5Ccos%7Bx%7D%7D%7B2%7D%7D)
sin 15°
The double of 15º is 30º. First quadrant, so the sine is positive.
![\sin{15} = sqrt{\frac{1 - \cos{30}}{2}}](https://tex.z-dn.net/?f=%5Csin%7B15%7D%20%3D%20sqrt%7B%5Cfrac%7B1%20-%20%5Ccos%7B30%7D%7D%7B2%7D%7D)
Since ![\cos{30} = 0.866](https://tex.z-dn.net/?f=%5Ccos%7B30%7D%20%3D%200.866)
![\sin{15} = sqrt{\frac{1 - \cos{30}}{2}} = \sqrt{\frac{1 - 0.866}{2}} = 0.2588](https://tex.z-dn.net/?f=%5Csin%7B15%7D%20%3D%20sqrt%7B%5Cfrac%7B1%20-%20%5Ccos%7B30%7D%7D%7B2%7D%7D%20%3D%20%5Csqrt%7B%5Cfrac%7B1%20-%200.866%7D%7B2%7D%7D%20%3D%200.2588)
sin 15° = 0.2588
Answer: 135.2 °F
Step-by-step explanation:
The temperature decreases at a rate of 2.3 °F per minute.
This means that in 25 minutes, the temperature would have reduced by:
= 2.3 * 25
= 57.5°F
If the original temperature was 192.7 °F, the temperature after 25 minutes will be:
= 192.7 - 57.5
= 135.2 °F
Answer:
10, 19 and 57
Step-by-step explanation:
let the first number be a, the second be b and the third be c
a+b+c=86
the second number is 9 less than the first
a=b+9------i
b=a-9
the third number is 3 times the first
c=3a------ii
a=c/3
therefore
b+9=c/3
c=3(b+9)
b+9+b+3(b+9)=86
b+9+b+3b+27=86
collecting like terms
5b=86-(27+9)
5b=86-36
5b=50
therefore
b=10
recall i to solve for a
a=b+9
a=10+9
a=19
recall ii to solve for c
c=3a
c=3*19
c=57