at 11:19 i dont understand how/why the ratio (DC:CB=1:2) means DC is half of CB? because doesn't this ratio simply mean DC is 1/3 and CB is 2/3? part c is kind of confusing...
DC:CB = 1:2 Based on this ratio, DB consists of 3 parts. DC is 1 part of DB. CB is 2 parts of DB. Vector CB=a and 2 parts represent a. It follows that 1 part must represent 1/2 a which equals vector DC. In this case, we only know vector CB and not vector DB. So, this sort of reasoning applies in this case. I hope this helps.
Amazing video, I finally understand proofs!
For question c can't you also use OA TO AC?
thx for the video
Thank You So Much!
how is -b + a = a - b?
why is -a + -1/2a equal to -3/2a? algebraic wise i don't understand
because its -2/2a - 1/2a
the coefficient of a is still there as 1 but you write it up
if you did though it would be a mixed fraction
1 1/2 = 3/2
👍
but u would never be asked the first example in an exam
useful
what about parallel line proof
6:45. =b + 1/2a - 1/2b = 1/2a + 1/2b Where did the first b go?
+Matthew Throne obviously b -1/2 b = 1/2 b :)
so b minus half a b is half a b
Ok, I got it. Thanks :)
@@MatthewThrone obviously b -1/2 b = 1/2 b :)
so b minus half a b is half a b obviously b -1/2 b = 1/2 b :)
so b minus half a b is half a b
at 11:19 i dont understand how/why the ratio (DC:CB=1:2) means DC is half of CB? because doesn't this ratio simply mean DC is 1/3 and CB is 2/3? part c is kind of confusing...
1 half of 2 parts is one part.
CB is 2 parts.
1 half of CB is one part.
DC is equal to one part.
Therefore DC is 1 half of CB
DC:CB = 1:2
Based on this ratio, DB consists of 3 parts. DC is 1 part of DB. CB is 2 parts of DB. Vector CB=a and 2 parts represent a. It follows that 1 part must represent 1/2 a which equals vector DC. In this case, we only know vector CB and not vector DB. So, this sort of reasoning applies in this case. I hope this helps.
Was confused but now I get the easiest substitution
Probably gonna fail my exam tomorrow. Fuck maths