108k views
0 votes
Need help with Question seven, on the topic of trigonometric functions.

Need help with Question seven, on the topic of trigonometric functions.-example-1
User WhoSayIn
by
8.1k points

1 Answer

6 votes

Answer:


\cos \: 2 \theta = (1)/(2) \\ \\ \therefore \: \cos \: 2 \theta = \cos \: 60 \degree \\ \therefore \: \cos \: 2 \theta = \cos \: (180 \degree - 120\degree ) \\ ( \because \: \theta \: lies \: between \: - 90 \degree \: and \: 90 \degree)\\ \therefore \: \cos \: 2 \theta = - \cos \: 120 \degree \\ \therefore \: 2 \theta = - 120 \degree \\ \therefore \: \theta = ( - 120 \degree)/(2) \\ \huge \red{\therefore \: \theta}\pink {= } \orange{ - 60 \degree}

User Gebitang
by
8.5k points

No related questions found

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

9.4m questions

12.2m answers

Categories