Question

$6(si{n}^6\theta +co{s}^6\theta )-9(si{n}^4\theta +co{s}^4\theta )$ is equal to

• A. -1
• B. 1
• C. -3
• D. 3

Answer 1

The correct option is C

-3

$si{n}^6\theta +co{s}^6\theta =(si{n}^2\theta +co{s}^2\theta {)}^3-3si{n}^2\theta co{s}^2\theta (si{n}^2\theta +co{s}^2\theta )si{n}^4\theta +co{s}^4\theta =(si{n}^2\theta +co{s}^2\theta {)}^3-2si{n}^2\theta co{s}^2\theta (si{n}^2\theta +co{s}^2\theta )$