more trig help please

[FrogyJil]

i need help with this problem i have tried

Factor and simplify cos^4x - 2 cos^2x sin^2x + sin^4x

for clarification ^ means rased to that power

i have tried and have gotten thus far but am stumped with where to go next

cos^2 x + sin^2 x ( cos^2 x - 2 + sin^2 x)

1 (cos^2 x - 2 + sin^2 x)

i cant figure out what to do next please help

 

[stapel]

See if you can see the similar pattern:

. . . . .x² - 2xy + y<sup>2<sup>

How would you factor the above?

Apply the same methodology to your exercise.

Eliz.