cos (2x) = cos x
2 cos^2 x -1 = cos x using the double angle formula
2 cos ^2 x -cos x -1 =0
factor
(2 cos x+1) ( cos x -1) = 0
using the zero product property
2 cos x+1 =0 cos x -1 =0
2 cos x = -1 cos x =1
cos x = -1/2 cos x=1
taking the arccos of each side
arccos cos x = arccos (-1/2) arccos cos x = arccos 1
x = 120 degrees x=-120 degrees x=0
remember you get 2 values ( 2nd and 3rd quadrant)
these are the principal values
now we need to add 360
x = 120+ 360n x=-120+ 360n x = 0 + 360n where n is an integer
Answer:
Sankore University
Step-by-step explanation:
Answer:
A) 24
Step-by-step explanation:
4!
4 x 3 x 2 x 1
24
Step-by-step explanation:
No. of possible selections= 5+4+3= 12
Probability of selecting drama= 3÷12
= 1÷4
PLEASE MARK BRAINLIEST.
Answer:
A. 24+24+120+160+200
Step-by-step explanation:
Surface area of the triangular prism= addition of the area of each shape that forms the prism
There are two triangles
Area of a triangle=1/2*base*height
=1/2*8*6
=1/2*48
=24
Area of two triangles=24+24
There are 3 rectangles with different dimensions
Back rectangle=length×width
=20×6
=120
Bottom rectangle=length ×width
=20x8
=160
Top rectangle=length × width
=20×10
=200
Surface area =Area of two triangles + Back rectangle + Bottom rectangle + Top rectangle
=24+24+120+160+200