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Maths question...Urgent help please!!

How to solve the equation 2cos^2 x+sin2x=1...I know that I should put them into the form like cos(x+a), but I don't know what to do with the different angles cuz the first part is x but the second part is 2x
Original post by Oliviazh
How to solve the equation 2cos^2 x+sin2x=1...I know that I should put them into the form like cos(x+a), but I don't know what to do with the different angles cuz the first part is x but the second part is 2x


Please post this in the maths forum :h:

You've identified the problem - that one is in terms of 2x and the other in x, and you want them to be the same so you can use Rcos(x+a) (or sin, but you will be able to figure it out when you need to).. So what can you do?
Reply 2
Original post by SeanFM
Please post this in the maths forum :h:

You've identified the problem - that one is in terms of 2x and the other in x, and you want them to be the same so you can use Rcos(x+a) (or sin, but you will be able to figure it out when you need to).. So what can you do?


I know what to do now...Don't know how could I be so stupid before:biggrin:
Reply 3
You could take the 2cos2x 2\cos^2 x away from both sides giving sin2x=12cos2x \sin 2x = 1-2\cos^2 x

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