Question

What is the distance between focii when distance between directrices is 100 mm and length of major axis is 80 mm

Answer 1

Answer

From Ellipse

=64 mm

sorry

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Answer 2

$\huge\bf\mathscr\pink{Your\: Answer}$

64 mm

step-by-step explanation:

For the ellipse,

Given that,

Distance between directrices = 100 mm

=> 2a/e = 100 .......................(i)

where,

e is the ecentricity of the ellipse.

Also,

length of major axis = 80 mm

=> 2a = 80 mm ........................(ii)

putting the value of 2a from eqn (ii) in eqn (i),

we get,

80/e = 100

=> e = 80/100

Now,

we know that ,

distance between the focii = 2ae

=> distance between focii = 80× 80/100 mm

=> distance between focii = 64 mm