conics easy q. (1 Viewer)

[elliottjohnson]

I've just started conics can someone help out. cant seem to get the right answer??

x^2/16 + y^2/36 = 1
find b. the eccentricity
c. the foci
and e. the equations of directricies

I keep getting my e value as sqroot5/3

how is it the correct answer of sqroot20/6 ??

 

[ninetypercent]

e = sqroot 20/6

Realise that b^2 is larger than a^2 in this equation, hence the formula for eccentricity is different.

 

[elliottjohnson]

thanks!