Use the Double-Angle Identity to find the exact value for cos 2x given sinx= square root of 2/4
Favorites|Homepage
Subscriptions | sitemap
HOME > > Use the Double-Angle Identity to find the exact value for cos 2x given sinx= square root of 2/4

Use the Double-Angle Identity to find the exact value for cos 2x given sinx= square root of 2/4

[From: ] [author: ] [Date: 12-04-10] [Hit: ]
. . . .. .......
Use the Double-Angle Identity to find the exact value for cos 2x given sinx= square root of 2/4

-
If sin x = sqrt(2) / 4, then sin^2 x = 2 / 16 = 1/8

Because cos 2x = 1 - 2 sin^2 x,

cos 2x = 1 - 2(1/8)
= 1 - 1/4
= 3/4

-
Is that sinx = √(2/4) or sinx = (√2)/4

For sin(x) = √2/4 = (√2)/4

cos(2x) = 1 - 2sin²x
. . . . . . = 1 - 2((√2)/4)²
. . . . . . = 1 - 2(2/16)
. . . . . . = 1 - 1/4
. . . . . . = 3/4

For sin(x) = √(2/4) = √(1/2)

cos(2x) = 1 - 2sin²x
. . . . . . = 1 - 2(√(1/2)²
. . . . . . = 1 - 2(1/2)
. . . . . . = 1 - 1
. . . . . . = 0

-
1 - cos(2x) = 2 *(sin(x))^2

cos(2x) = 1 - 2 *sqrt (2)/4 = 1-1/sqrt(2)

We found this without taking care about x itself as an angle or so on
1
keywords: root,Angle,find,sinx,Double,cos,given,value,square,for,Use,exact,of,to,Identity,the,Use the Double-Angle Identity to find the exact value for cos 2x given sinx= square root of 2/4
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .