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Find sin 2x, cos 2x, and tan 2x from the given information.Find sin 2x, cos 2x, and tan...

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gulnur3 | Student, Grade 10 | (Level 1) eNoter

Posted April 26, 2012 at 7:07 PM via web

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Find sin 2x, cos 2x, and tan 2x from the given information.

Find sin 2x, cos 2x, and tan 2x from the given information.

 

sin x= 8/17  ,   x in Quadrant I   sin 2x =____________   cos 2x=____________   tan 2x=____________

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hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted April 26, 2012 at 7:59 PM (Answer #1)

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Given that :

`sinx = 8/17`

We know that:

`sin^2 x + cos^2 x = 1 `

`==> cosx = sqrt(1-sin^2 x)= sqrt(1- 8^2/17^2) = 15/17`

==> `cosx = 15/17`

Now we will find the required identity.

==> We know that `sin2x = 2sinx cosx `

`==> sin2x = 2*8/17 * 15/17 = 240/17`

`==> cos2x = cos^2 x - sin^2 x = (15/17)^2 - (8/17)^2 = 161/289`

`==gt tan2x = (sin2x)/(cos2x)= (240/17)/(161/289)= (240*17)/(161) ~~ 25.34`

 

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