Question

I'll give a medal
What is the foci of 4x2 + 9y2 = 36

Answer 1

Write it as \[
\frac {x^2}9 + \frac {y^2}4 =1

\]
a=3, b=2;
\[
c^2=a^2 - b^2= 9-4=5\\
c=\pm \sqrt 5
Foci=(0,\pm \sqrt 5)
\]

Answer 2

thanks

Answer 3

YW

Answer 4

i think foci are \[\left( \pm \sqrt{5},0 \right)\]