Trig identiteite - cos3A

Trig identiteite - cos3A

by Samantha Novello -
Number of replies: 1

B e w y s space d a t space cos 3 straight A equals 4 c o s cubed straight A minus 3 c o s straight A


(Edited by Marna Zuhlsdorff - original submission Thursday, 20 February 2020, 4:29 PM)

In reply to Samantha Novello

Re: Trig identiteite

by Marna Zuhlsdorff -
Hi Samantha

Baie dankie vir jou vraag en antwoord. Ek het 'n onderwyser gehad wat altyd gesê het jy mag net met een kant van 'n identiteit werk...ek dink nie dis waar nie, maar dalk het sy geweet ek sal bietjie vasbyt as ek vashaak en dan eventually by die antwoord uit kom? (",)

Jy kan hier click om weer die videos oor identiteite met saamgestelde hoeke te kyk.

Hier is my antwoord:
table row cell cos 3 straight A equals 4 c o s cubed straight A minus 3 c o s straight A end cell blank blank blank row cell L K equals cos 3 straight A end cell blank blank blank row cell equals cos open parentheses 2 straight A plus straight A close parentheses end cell blank blank blank row cell equals cos 2 AcosA minus sin 2 AsinA end cell blank blank blank row cell equals cos 2 AcosA minus open parentheses 2 s i n A c o s A close parentheses sinA end cell blank blank cell Vervang space eers space sin 2 straight A comma space want space daar space is space net space een space opsie end cell row cell equals cos 2 AcosA minus 2 sin squared AcosA end cell blank blank Vereenvoudig row cell equals cos 2 AcosA minus 2 open parentheses 1 minus c o s squared straight A close parentheses cosA end cell blank blank cell asterisk times Vervang space sin squared straight A space met space 1 minus cos squared straight A end cell row cell equals cos 2 AcosA minus 2 cosA open parentheses 1 minus cos squared straight A close parentheses end cell blank blank Herrangskik row cell equals cos 2 AcosA minus 2 cosA plus 2 cos cubed straight A end cell blank blank Vereenvoudig row cell equals open parentheses 2 c o s squared straight A minus 1 close parentheses cosA minus 2 cosA plus 2 cos cubed straight A end cell blank blank cell asterisk times asterisk times Vervang space cos 2 straight A space met space 2 cos squared straight A minus 1 end cell row cell equals cosA open parentheses 2 cos squared straight A minus 1 close parentheses minus 2 cosA plus 2 cos cubed straight A end cell blank blank Herrangskik row cell equals 2 cos cubed straight A minus cosA minus 2 cosA plus 2 cos cubed straight A end cell blank blank Vereenvoudig row cell equals 4 cos cubed straight A minus 3 cosA end cell blank blank blank row cell equals RK end cell blank blank blank end table

asterisk times Vervang space sin squared A space m e t space 1 minus cos squared A table row cell w a n t   space sin squared A plus cos squared A equals 1 end cell blank blank cell graad space 11 space identeit end cell row cell sin squared A equals 1 minus cos squared A end cell blank blank blank end table

My finale antwoord het nie 'n sin squared x in nie, so ek weet ek moet van hom ontslae raak.

** Hoekom cos 2 straight A equals 2 cos squared straight A minus 1

EK wil met 'n cos cubed A opeindig, so my keuses was open parentheses cos squared A minus sin squared A close parentheses of open parentheses 2 cos squared straight A minus 1 close parentheses, maar ek wil nie 'n sin squared A hê nie, daarom gebruik ek cos 2 straight A equals 2 cos squared straight A minus 1


Ek het ook 'n video oor jou som gemaak (",) - jy kan hier click om dit te kyk.

Marna