Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 11-science Answered

The following questions may kindly be answered.
Asked by tps.mjmdr | 16 Jun, 2018, 08:37: PM
Expert Answer
cosθ + cos(∏+θ) + .....+cos(n∏+θ)
Consider,
cos(∏+θ) = cos∏cosθ - sin∏sinθ
As sinn∏ is always zero and cos∏ = -1
cos(∏+θ) = -cosθ
similarly cos2∏ = 1
Now we have two cases
i) n is odd
then cos(n∏+θ) = (-1)n cosθ = -cosθ
ii) n is even
then cos(n∏+θ) = (-1)n cosθ = cosθ
USe this and solve it further
Answered by Sneha shidid | 19 Jun, 2018, 11:04: AM

Concept Videos

CBSE 11-science - Maths
Asked by defence | 27 Apr, 2019, 08:55: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by ramakoti61 | 09 Jul, 2018, 08:45: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by tps.mjmdr | 16 Jun, 2018, 08:37: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT