Let us start subtracting 3 cos theta both sides so that we may get all theta terms on left side only
It is now : 4 cos theta - 3 cos theta = - (sqrt3)/ 2
1 cos theta = -( sqrt 3 ) /2
we know cos (pi-x)= - cos x And cos (pi+ x)= - cos (x)
********* let us first use :
- Cos ( pi - theta) = - ( sqrt 3 )/2
this implies cos (pi- theta )= (sqrt 3) /2
cos ( pi - theta )= cos (pi /6)
pi- theta = pi/6
pi- pi/6 = theta
5 pi/6 = theta
one of teh answer is 5 pi/6 . another value of theta would be :
(2pi - 5pi/6)= 7pi/6
Answer: 5 pi/6 and 7 pi/6
I can solve with 2 methods:
I. Because the discount is 15 % of 18 $ , the price will be (100-15=85) 85 % of 18 $
18*85/100= 15,3 $ ( the sale price)
II. The discount is 15 % of 18$
15*18/100= 2,7$ ( the discount)
then I decrease it from the regularly price
18$-2,7$=15,3 $ (the sale price)
Personally I believe the first is an easier method.
I hope you understand and you can apply this in every similary problem.
Answer:
D
Step-by-step explanation:
It would be a cone with a radius of 4 units rotating around y-axis.
