Question

PLEASE HELP

Answer 1

Answer:

Option 1 is correct.

Step-by-step explanation:

Given the expression

$sin^4x=\frac{1}{8}{(3-4cos2x+cos4x)}$

we have to complete the fourth step to prove the above result.

$sin^4x=(sin^2x)^2\\\\sin^4x=(\frac{1-cos2x}{2})^2 \\\\sin^4x=\frac{1-2cos2x+cos^22x}{4}$

As, $cos^2x=\frac{1+cos2x}{2}$

⇒  $cos^{2}2x=\frac{1+cos4x}{2}$

Hence, the next step becomes

$sin^4x=\frac{1-2cos2x+\frac{1+cos4x}{2}}{4}$

Hence, option 1 is correct.

Answer 2

A
p/s : follow me and I will help you more about maths :))))