Cos^2-sin^2=1/3 so what is cos^4-sin^4

Mkon asked Nov 25, 2023

64,422 views

10 votes

Cos^2-sin^2=1/3
so what is cos^4-sin^4

Mkon asked Nov 25, 2023

by Mkon

2.7k points

Your comment on this question:

Email me at this address if a comment is added after mine:Email me if a comment is added after mine

Privacy: Your email address will only be used for sending these notifications.

Email me at this address if my answer is selected or commented on:Email me if my answer is selected or commented on

Privacy: Your email address will only be used for sending these notifications.

12 votes

Explanation:

$cos ^(2) x - \sin ^(2) x = (1)/(3)$

$((cos ^(2)x - \sin ^(2) x)(cos ^(2)x + \sin ^(2) x))/((cos ^(2)x + \sin ^(2) x)) = (1)/(3)$

$((cos ^(4)x - \sin ^(4) x))/(1) = (1)/(3)$

as cos²x+sin²x=1

Hence

cos⁴x-sin⁴x=1/3

AgilePro answered Nov 28, 2023

3.0k points

Email me at this address if a comment is added after mine:Email me if a comment is added after mine

Privacy: Your email address will only be used for sending these notifications.

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

1.6m questions

2.0m answers