The answer to your question is 3
Answer:
A, C
Step-by-step explanation:
Actually, those questions require us to develop those equations to derive into trigonometrical equations so that we can unveil them or not. Doing it only two alternatives, the other ones will not result in Trigonometrical Identities.
Examining
A) True

Double angle 
B) False,
No further development towards a Trig Identity
C) True
Double Angle Sine Formula 

D) False No further development towards a Trig Identity
![[sin(x)-cos(x)]^{2} =1+sin(2x)\\ sin^{2} (x)-2sin(x)cos(x)+cos^{2}x=1+2sinxcosx\\ \\sin^{2} (x)+cos^{2}x=1+4sin(x)cos(x)](https://tex.z-dn.net/?f=%5Bsin%28x%29-cos%28x%29%5D%5E%7B2%7D%20%3D1%2Bsin%282x%29%5C%5C%20sin%5E%7B2%7D%20%28x%29-2sin%28x%29cos%28x%29%2Bcos%5E%7B2%7Dx%3D1%2B2sinxcosx%5C%5C%20%5C%5Csin%5E%7B2%7D%20%28x%29%2Bcos%5E%7B2%7Dx%3D1%2B4sin%28x%29cos%28x%29)
Answer= 285000
How to= the number you are dividing by has a decimal move the decimal point all the way to the right counting the number of places you’ve moved it to. Then move the decimal point in the number you’re dividing the same number of places to the right
X= 4 this solution is valid
X= 20 this solution is valid