Answer:
a) ![tan (157.5) = \frac{1-cos 315}{sin315}](https://tex.z-dn.net/?f=tan%20%28157.5%29%20%3D%20%5Cfrac%7B1-cos%20315%7D%7Bsin315%7D)
b)
![sin (165) =\sqrt{ \frac{1-cos (330) }{2}}](https://tex.z-dn.net/?f=sin%20%28165%29%20%3D%5Csqrt%7B%20%5Cfrac%7B1-cos%20%28330%29%20%7D%7B2%7D%7D)
c)
![sin^{2} (157.5) = \frac{1-cos (315) }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28157.5%29%20%3D%20%5Cfrac%7B1-cos%20%28315%29%20%7D%7B2%7D)
d)
cos 330° = 1- 2 sin² (165°)
Step-by-step explanation:
<u><em>Step(i):-</em></u>
By using trigonometry formulas
a)
cos2∝ = 2 cos² ∝-1
cos∝ = 2 cos² ∝/2 -1
1+ cos∝ = 2 cos² ∝/2
![cos^{2} (\frac{\alpha }{2}) = \frac{1+cos\alpha }{2}](https://tex.z-dn.net/?f=cos%5E%7B2%7D%20%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%29%20%3D%20%5Cfrac%7B1%2Bcos%5Calpha%20%7D%7B2%7D)
b)
cos2∝ = 1- 2 sin² ∝
cos∝ = 1- 2 sin² ∝/2
![sin^{2} (\frac{\alpha }{2}) = \frac{1-cos\alpha }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%29%20%3D%20%5Cfrac%7B1-cos%5Calpha%20%7D%7B2%7D)
<u><em>Step(i):-</em></u>
Given
![tan\alpha = \frac{sin\alpha }{cos\alpha }](https://tex.z-dn.net/?f=tan%5Calpha%20%3D%20%5Cfrac%7Bsin%5Calpha%20%7D%7Bcos%5Calpha%20%7D)
we know that trigonometry formulas
![sin\alpha = 2sin(\frac{\alpha }{2} )cos(\frac{\alpha }{2} )](https://tex.z-dn.net/?f=sin%5Calpha%20%3D%202sin%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%29cos%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%29)
1- cos∝ = 2 sin² ∝/2
Given
![tan(\frac{\alpha }{2} ) = \frac{sin(\frac{\alpha }{2} )}{cos(\frac{\alpha }{2}) }](https://tex.z-dn.net/?f=tan%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%29%20%3D%20%5Cfrac%7Bsin%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%29%7D%7Bcos%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%29%20%7D)
put ∝ = 315
![tan(\frac{315}{2} ) = \frac{sin(\frac{315 }{2} )}{cos(\frac{315 }{2}) }](https://tex.z-dn.net/?f=tan%28%5Cfrac%7B315%7D%7B2%7D%20%29%20%3D%20%5Cfrac%7Bsin%28%5Cfrac%7B315%20%7D%7B2%7D%20%29%7D%7Bcos%28%5Cfrac%7B315%20%7D%7B2%7D%29%20%7D)
multiply with ' 2 sin (∝/2) both numerator and denominator
![tan (\frac{315}{2} )= \frac{2sin^{2}(\frac{315)}{2} }{2sin(\frac{315}{2} cos(\frac{315}{2}) }](https://tex.z-dn.net/?f=tan%20%28%5Cfrac%7B315%7D%7B2%7D%20%29%3D%20%5Cfrac%7B2sin%5E%7B2%7D%28%5Cfrac%7B315%29%7D%7B2%7D%20%20%7D%7B2sin%28%5Cfrac%7B315%7D%7B2%7D%20cos%28%5Cfrac%7B315%7D%7B2%7D%29%20%7D)
Apply formulas
![sin\alpha = 2sin(\frac{\alpha }{2} )cos(\frac{\alpha }{2} )](https://tex.z-dn.net/?f=sin%5Calpha%20%3D%202sin%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%29cos%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%29)
1- cos∝ = 2 sin² ∝/2
now we get
![tan (157.5) = \frac{1-cos 315}{sin315}](https://tex.z-dn.net/?f=tan%20%28157.5%29%20%3D%20%5Cfrac%7B1-cos%20315%7D%7Bsin315%7D)
b)
![sin^{2} (\frac{\alpha }{2}) = \frac{1-cos\alpha }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%29%20%3D%20%5Cfrac%7B1-cos%5Calpha%20%7D%7B2%7D)
put ∝ = 330° above formula
![sin^{2} (\frac{330 }{2}) = \frac{1-cos (330) }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28%5Cfrac%7B330%20%7D%7B2%7D%29%20%3D%20%5Cfrac%7B1-cos%20%28330%29%20%7D%7B2%7D)
![sin^{2} (165) = \frac{1-cos (330) }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28165%29%20%3D%20%5Cfrac%7B1-cos%20%28330%29%20%7D%7B2%7D)
![sin (165) =\sqrt{ \frac{1-cos (330) }{2}}](https://tex.z-dn.net/?f=sin%20%28165%29%20%3D%5Csqrt%7B%20%5Cfrac%7B1-cos%20%28330%29%20%7D%7B2%7D%7D)
c )
![sin^{2} (\frac{\alpha }{2}) = \frac{1-cos\alpha }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28%5Cfrac%7B%5Calpha%20%7D%7B2%7D%29%20%3D%20%5Cfrac%7B1-cos%5Calpha%20%7D%7B2%7D)
put ∝ = 315° above formula
![sin^{2} (\frac{315 }{2}) = \frac{1-cos (315) }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28%5Cfrac%7B315%20%7D%7B2%7D%29%20%3D%20%5Cfrac%7B1-cos%20%28315%29%20%7D%7B2%7D)
![sin^{2} (157.5) = \frac{1-cos (315) }{2}](https://tex.z-dn.net/?f=sin%5E%7B2%7D%20%28157.5%29%20%3D%20%5Cfrac%7B1-cos%20%28315%29%20%7D%7B2%7D)
d)
cos∝ = 1- 2 sin² ∝/2
put ∝ = 330°
![cos 330 = 1 - 2sin^{2} (\frac{330}{2} )](https://tex.z-dn.net/?f=cos%20330%20%3D%201%20-%202sin%5E%7B2%7D%20%28%5Cfrac%7B330%7D%7B2%7D%20%29)
cos 330° = 1- 2 sin² (165°)
The circumference is 12.56cm and the area is 12.56cm
He planted 92 of those because 12 times 6 is 72 and 72 plus 20 is 92 therefore the answer is 92
Answer:
40
Step-by-step explanation:
128 : 3 :: w : 8 proportion
3w = (8)(128) product means/extremes
w = 341 ⅓ cars