x² = 1 - 25y² this one is a little tricky.... let's put it into standard form ...add 25y^2 to both sides
x^2 + 25y^2 = 1 this can be written as follows
x^2/ 1 + y^2 / (1/25) = 1
The center is at (0,0)..........the major axis is 2 units long and lies along the x axis so the foci will too ....[the minor axis lies along the y axis and is 2/5 units long ]
Using a = 1 and b = 1/5 the foci will be given by :
( ± √ [a^2 - b^2] , 0 ) =
( ± √ [ 1^2 - (1/5)^2], 0 ) =
( ± √ [ 1 - 1/25], 0 ) =
( ± √ [24/25], 0) =
( ± √ [ 6 * 4 ] / 5, 0 ) =
( ± (2/5)√6 , 0 ) ≈ ( ± .979, 0)
Here's a graph : https://www.desmos.com/calculator/vrzd1pwugc