I think he just wrote down the result in the mark scheme at the end. he just got confused and thought: cos (4cos - 1) goes to (4cos^2 - 4cos). the right answer is: (4cos^2 - cos) he multiplied by 4 again which is fine dw because his thought process was correct.
1 0:20
2 1:40
3 6:48
4 8:55
5! 12:25
6 16:00
7 20:51
8 25:11
9 31:02
10 38:15
11 41:20
12! 47:07
13! 53:19
14 59:36
15! 1:04:04
48:45 how did you expand to get 4 cos theta instead of just cos theta
same
he seems to ignore his mistake, it's fine though your right, if you do the equation after normally you get the correct answer.
I think he just wrote down the result in the mark scheme at the end. he just got confused and thought: cos (4cos - 1) goes to (4cos^2 - 4cos). the right answer is: (4cos^2 - cos) he multiplied by 4 again which is fine dw because his thought process was correct.
The cost for question 8 b (ii), is incorrect, it is £93.03
how did u go from 8 * 2/3 = 4 at 15:57 bro
By using my calculator
its 8 to the power of 2/3, not 8 * 2/3
how did you get k < 0 and not k > 0 in 1:03:56
I think it's because he divided by k, flip the arrow flip the sign???
for 19:43 all u had to do was 9 minus the square root of 3.2 btw u over complicated it
he was looking for multiple values, not just one. If you did that, you would just get one value. Not answering the question correctly
correction, you would get a +- value which again, isnt what you want
first