Recent content by snooooooooooz

but where did the negative come from?

Sorry, "foil" is distributive property. I'm just going to assume that sin^4x + cos^4x = 1- but how?

So I got sin^4x +2sin^2xcos^2x + cos^4x . How would drop the sin^4x and cos^4x to make that into a 1-?

But if you foil that out you get sin^4x + sin^2xcos^2x + cos^2xsin^2x + cos^4x.

ok.. so my next line is: 1 x sin^2x +cos^2x?

ok so if I take sin^2x + cos^2x out of sin^4+cos^4x that means I'm left with sin^2x + cos^2x. Since sin^2x + cos^2x = 1 and cos^2x = 1-sin^2x there is NO cos^2x at the end to multiply by. There is no way I can see how sin^4x + cos^4x can equal 1-2sin^2x cos^2x

EDIT: Actually, I don't see how you can use completing the square to factor sin^4x + cos^4x.

From the first line my next line is: sin^3x/cos^3x / 1/cos^2x + cos^3x/sin^3x / 1/sin^2x then, sin^3x/cos^3x x cos^3x / 1/cos^2x x cos^3x + cos^3x/sin^3x x sin^3x / 1/sin^2x x sin^3x then, sin^4x + cos^4x / sinx x cosx so, as you can see, I'm stuck. You can't simplify the...

Yes, you're proving that one side equals the other side.

... I would like your help, I just don't know what to type out. Basically, I rearranged the equation using sine and cosine and I ended up with sin^4x + cos^4x/sinxcosx.

I'm solving a pretty descent trig identity question, but I'm stuck. I'm not going to type out the original question, but here the section that I'm stuck on: sin^4x + cos^4x and here is what I have to prove: 1-2sin^2xcos^2x I know that I'm really close, I just can't get this section. Any help...