Answer:
Step-by-step explanation:
cos (x/2)=cos x+1
cos (x/2)=2cos ²(x/2)
2 cos²(x/2)-cos (x/2)=0
cos (x/2)[2 cos (x/2)-1]=0
cos (x/2)=0=cos π/2,cos (3π/2)=cos (2nπ+π/2),cos(2nπ+3π/2)
x/2=2nπ+π/2,2nπ+3π/2
x=4nπ+π,4nπ+3π
n=0,1,2,...
x=π,3π
or x=180°,540°,...
180°∈[0,360]
so x=180°
or
2cos(x/2)-1=0
cos (x/2)=1/2=cos60,cos (360-60)=cos 60,cos 300=cos (360n+60),cos (360n+300)
x/2=360n+60,360n+300
x=720n+120,720n+300
n=0,1,2,...
x=120,300,840,1020,...
only 120° and 300° ∈[0,360°]
Hence x=120°,180°,300°
Answer: 14500
Step-by-step explanation:
Let the price of the mobile phone before the GST was added be represented by x.
Therefore,
x + (12% × x) = 16240
x + 0.12x = 16240
1.12x = 16240
x = 16240/1.12
x = 14500
The price of the mobile phone before the GST was added was 14500
Answer:
217
Step-by-step explanation:
62x3=186+ .5 of 62 which is 31
186+31=217
Equation 1 ==> y - x = -13
Equation 2 ==> -4x + 3y = -51
3(y - x) = 3(-13)
Equation 3 ==> 3y - 3x = -39
Equation 2 - 3
= (3y - 3y) + ( -4x - (-3x) ) = -51 - (-39)
-x = -12
x = 12
Substitude x into equation 1
y - 12 = -13
y = -1
Answer:
A. 2 acute and 1 right angle.
