Answer:
22 m
Step-by-step explanation:
Total distance travelled by marble while falling down = height above surface of lake + depth of lake = 15 + 7 = 22 m
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
Hey man I got u. The answer for this question is B. Peace
The answer is 6:15, but if u need to simplify the answer would be 2:5.
I think it’s v=-20 i showed you my work if that helps :)
