1.

Prove that: `cos175^(@)+cos65^(@)+cos55^(@)=0`

Answer» LHS `=cos175^(@)+cos65^(@)+cos55^(@)`
`=2cos120^(@)cos55^(@)+cos55^(@)`
`=2cos(180^(@)-60^(@))cos55^(@)+cos55^(@)`
`=-2cos60^(@)+cos55^(@)`
`=-2(1/2)cos55^(@)+cos55^(@)`
`-cos55^(@)+cos55^(@)=0`
=RHS Hence Proved.


Discussion

No Comment Found

Related InterviewSolutions