Trig Identity (1 Viewer)

[EvoRevolution]

really

 

[Drongoski]

really

A³ + B³ not equal to (A + B)³ - 3 A²B²

 

[Timothy.Siu]

really

nope, the way u were trying doing it was the way i did.

note that (x+y)³=x³+3x²y+3xy²+y³
this is the part u got wrong.

however if u look at drogonski's method,
he used the factorisation of cubes,
x³+y³=(x+y)(x²+xy+y²)

this shows two different ways of manipulating x³+y³ of which the latter was better for this question.

 

[EvoRevolution]

yea lol, it doesn't work bbut i had the right idea anyway

next question

 

[EvoRevolution]

yea Tim u fixed it up way before
oops

 

[EvoRevolution]

nope, the way u were trying doing it was the way i did.
note that (x+y)³=x³+3x²y+3xy²+y³
this is the part u got wrong.

lol its problably wrong but anyway