Math - A level
How do I prove this identity:
(cosx + 3sinx)^2 is equivalent to 5-4cos2x + 3sin2x?
I managed to get the 3sin2x by doing 3(2sinxcosx) which is just 3sin2x and managed to get 10-9cos2x but as you can see its 5 -4cos2x...
(cosx + 3sinx)^2 is equivalent to 5-4cos2x + 3sin2x?
I managed to get the 3sin2x by doing 3(2sinxcosx) which is just 3sin2x and managed to get 10-9cos2x but as you can see its 5 -4cos2x...
Original post by sweetescobar
How do I prove this identity:
(cosx + 3sinx)^2 is equivalent to 5-4cos2x + 3sin2x?
I managed to get the 3sin2x by doing 3(2sinxcosx) which is just 3sin2x and managed to get 10-9cos2x but as you can see its 5 -4cos2x...
(cosx + 3sinx)^2 is equivalent to 5-4cos2x + 3sin2x?
I managed to get the 3sin2x by doing 3(2sinxcosx) which is just 3sin2x and managed to get 10-9cos2x but as you can see its 5 -4cos2x...
Can you upload your working? It should be just a case of mapping the squared terms to double angles.
(edited 2 years ago)
Original post by sweetescobar
How do I prove this identity:
(cosx + 3sinx)^2 is equivalent to 5-4cos2x + 3sin2x?
I managed to get the 3sin2x by doing 3(2sinxcosx) which is just 3sin2x and managed to get 10-9cos2x but as you can see its 5 -4cos2x...
(cosx + 3sinx)^2 is equivalent to 5-4cos2x + 3sin2x?
I managed to get the 3sin2x by doing 3(2sinxcosx) which is just 3sin2x and managed to get 10-9cos2x but as you can see its 5 -4cos2x...
As advised, post your working! What other terms do you get to combine apart from the 6cosxsinx term when you expand the bracket, and what double angle identities do you know?
Quick Reply
Related discussions
- TSR Study Together - STEM vs Humanities!
- GCSE Exam Discussions 2024
- I have a lot OF A-level and GCSE Maths and Further Maths resources. Who's Interested?
- A level choices for imperial?
- a level maths
- which education board and a level should I pick for an extra subject?
- How important is maths in a-level physics?
- A Level Options?
- A level physics or chem?
- Economics degree
- What should I study with psychology and economics
- AS further maths
- Do I need A-Level maths to study economics at uni?
- Need help picking a levels
- maths a level
- Should I do maths a level?
- People who do Computer Science in Uni: How much mathematics do you do?
- Will universities accept maths and further maths as two?
- chemistry with/and maths degree with an access to he diploma?
- A level subjects for computer science at oxford n other unis
Latest
Trending
Last reply 4 days ago
Did Cambridge maths students find maths and further maths a level very easy?Last reply 2 weeks ago
Edexcel A Level Mathematics Paper 2 unofficial mark scheme correct me if wrongMaths
71
Trending
Last reply 4 days ago
Did Cambridge maths students find maths and further maths a level very easy?Last reply 2 weeks ago
Edexcel A Level Mathematics Paper 2 unofficial mark scheme correct me if wrongMaths
71
