Home
Class 12
MATHS
Prove that cos55^0+cos65^0+cos175^0=0...

Prove that `cos55^0+cos65^0+cos175^0=0`

Text Solution

Verified by Experts

LHS`=cos55^(@)+cos 65^(@)+cos175^(@)`
`=2cos(55^(@)+65^(@))/(2)cos(55^(@)-65^(@))/(2)+cos175^(@)`
`=2cos 60^(@)cos(-5^(@))+cos175^(@)`
`=2xx(1)/(2)cos5^(@)+cos(180^(@)-5^(@))`
`=cos5^(@)-cos5^(@)=0`
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRIC RATIOS AND TRANSFORMATION FORMULAS

    CENGAGE|Exercise Exercise 3.1|11 Videos

  • TRIGONOMETRIC RATIOS AND TRANSFORMATION FORMULAS

    CENGAGE|Exercise Exercise 3.2|7 Videos

  • TRIGONOMETRIC FUNCTIONS

    CENGAGE|Exercise SINGLE CORRECT ANSWER TYPE|38 Videos

  • TRIGONOMETRIC RATIOS FOR COMPOUND, MULTIPLE, SUB-MULTIPLE ANGLES, AND TRANSFORMATION FORMULAS

    CENGAGE|Exercise Multiple Correct Answers Type|6 Videos

Similar Questions

Explore conceptually related problems

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

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

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

Prove that: cos24^(0)+cos55^(@)+cos125^(@)+cos20460+cos300^(@)=(1)/(2)

Prove that: 4cos12^(0)cos48^(0)cos72^(0)=cos36^(@)

Prove that cos65^(@)+cos115^(0)=0

Prove that cos36^(@)cos72^(0)cos108^(0)cos144^(0)=(1)/(16)

Prove that: cos7^(0)cos14^(0)cos28^(0)cos56^(@)=(s in68^(0))/(16cos83^(@))

Prove that cos130^@+cos110^@+cos10^@=0 .

Prove that: cos20^(0)cos100^(@)+cos100^(@)cos140^(@)-cos140^(@)-cos140^(@)cos200^(@)=