Question

Prove that sin^4x - cos^4x= 1-2cos^2x

Answer 1

Step-by-step explanation:

Write

new 3 words and make

One sentence

using that word

will learn 21 words

Answer 2

----> To prove= sin^4x-cos^4x=1-2cos^2x

◆Taking LHS

◆sin^4x-cos^4x

◆(sin^2x-cos^2x) (sin^2x+ cos^2x) 【By identity (a+b)(a-b)=a^2-b^2】

◆(Sin^2x-Cos^2x)×(1)

◆(Because sin^2x+cos^2x=1)

◆(1-cos^2x)-cos^2x

◆1-2cos^2x