Let $a,$ $b,$ $c,$ and $d$ be real numbers such that $a^2 + b^2 = 8$ and $c^2 + d^2 = 13.$  Find
\[(ad - bc)^2 + (ac + bd)^2.\]
Question:
Let $a,$ $b,$ $c,$ and $d$ be real numbers such that $a^2 + b^2 = 8$ and $c^2 + d^2 = 13.$  Find
\[(ad - bc)^2 + (ac + bd)^2.\]
Answer:
Let's think step by step.

user
104
Let $a,$ $b,$ $c,$ and $d$ be real numbers such that $a^2 + b^2 = 8$ and $c^2 + d^2 = 13.$  Find
\[(ad - bc)^2 + (ac + bd)^2.\]
train