Asked by yang

prove that: sin²(3x) + cos²(3x) + sin²(x) - cos²(x) = 0
Answered by Anonymous
well, easy
sin^2 (3x)+cos^2(3x)=1
that leaves on the left
1-cos^2 x + sin^2 x
but 1-cos^2 x=sin^2 x
so, now you are left with
sin^2 x + sin^2 x which is NOT zero. The equation is false.
Answered by Steve
sin²(3x) + cos²(3x) = 1

1 + sin²(x) - cos²(x) = 2sin²(x)
not zero

I suspect you have a typo. A true assertion is

sin²(3x) + cos²(3x) - sin²(x) - cos²(x) = 0
Answered by yang
thank you
then how do you solve : sin²(3x) + cos²(3x) - sin²(x) - cos²(x) = 0
Answered by Steve
come on you know that

sin²(u) + cos²(u) = 1

so, the equation reduces to

sin²(3x) + cos²(3x) - (sin²(x) + cos²(x)) = 0
1 - 1 = 0
Answered by yang
thank you steve
There are no AI answers yet. The ability to request AI answers is coming soon!