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If sin(theta)=-(13/15) and cos(theta) >0, find the exact value of tan ( theta) 

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seerboldly | Student, Grade 10 | Salutatorian

Posted October 3, 2013 at 1:25 PM via web

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If sin(theta)=-(13/15) and cos(theta) >0, find the exact value of tan ( theta) 

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aruv | High School Teacher | Valedictorian

Posted October 3, 2013 at 1:38 PM (Answer #1)

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`sin(theta)=-13/15,and cos(theta)>0 => thetainIV` quadrant.

So will  `tan(theta)<0.`

`Thus`

`cosec(theta)=-15/13`

`cosec^2(theta)-1=cot^2(theta)`

`cot^2(theta)=56/169`

`cot(theta)=+-sqrt(56/169)`

`But tan(theta)<0`

`therefore`

`cot(theta)<0`

`=> cot(theta)=-sqrt(56/169)`

`therefore`

`tan(theta)=-13/sqrt(56)`

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