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If 3tan(theta-15^0)=tan(theta+15^0), the...

If `3tan(theta-15^0)=tan(theta+15^0),` then `theta` is equal to `n in Z)`

A

n`pi+pi/4`

B

`npi+pi/8`

C

`npi+pi/3`

D

none of these

Text Solution

Verified by Experts

`3tan(theta-15^@) = tan(theta+15^@)`
`=>(tan(theta+15^@))/(tan(theta-15^@)) = 3/1`
Using componendo and dividendo,
`=>(tan(theta+15^@)+tan(theta-15^@))/(tan(theta+15^@)-tan(theta-15^@)) = (3+1)/(3-1)`
`=>(sin(theta+15^@)/cos(theta+15^@)+sin(theta-15^@)/cos(theta-15^@))/(sin(theta+15^@)/cos(theta+15^@)-sin(theta-15^@)/cos(theta-15^@)) = 2`
`=>(sin(theta+15^@)cos(theta-15^@)+sin(theta-15^@)cos(theta+15^@))/(sin(theta+15^@)cos(theta-15^@)-sin(theta-15^@)cos(theta+15^@)) = 2`
`=>(sin(theta+15^@+theta-15^@))/(sin(theta+15^@-theta+15^@)) = 2`
`=>(sin2theta)/(sin30^@) = 2`
...
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