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:
Step-by-step explanation:
☁️ Answer ☁️
5. IS E (none of these)
Because I got:
-125y^5/162x
6. X = 5/3
Hope it helps.
Have a nice day noona/hyung.
A polynomial is an expression that contains several terms.
Examples include...
5x +1
5x^(-2) +1
Answer:
B. r + l = 45; 2r + 3l = 96
39 regular; 6 long-distance
Step-by-step explanation:
There were 45 baskets, so
(1) r + l = 45
There were 96 points in the game, so
(2) 2r + 3l = 96
Solve equation (1) for l
l = 45 – r Substitute the value for l in Equation (2)
2r + 3(45 – r) = 96 Remove parentheses
2r + 135 - 3r = 96 Combine like terms
-r + 135 = 96 Subtract 135 from each side
-r = -39 Multiply each side by -1
r = 39 Substitute the value of r in Equation (1)
39 + l = 45 Subtract 39 from each side
l = 6
===============
Check:
(1) 39 + 6 = 45
45 = 45
(2) 2×39 + 3×6 = 96
78 + 18 = 96
96 = 96
