Question

请问这一题怎么解，帮忙解答一下过程。

Answer 1

解：设x=x' y=y' 则
y(x,y)=y(x',y')=(x')²-2x'y'

x=tx' y=ty'

当x=tx' y=ty'时

y(x,y)=y(tx',ty')

=(tx')² - 2(tx')(ty')

=t²(x')² - 2t²x'y'
=t²[(x')² - 2x'y']
=t²y(x',y')
=t²y(x,y)
=t²(x²-2xy)
=t²x²-2t²xy