Archive
7th of March 2017
Mathematics
Q:

Please explain how to find the value of cos (-1710 degrees).

Shyam Soman.s - CBSE - Class XI Science

Tuesday, March 07, 2017 at 18:17:PM

A:

begin mathsize 16px style sine space and space cosineare space periodic space functions space with space period space 2 straight pi.
Therefore comma space the space value space of space straight a space trigonometrical space ratio space for space any space angle space is space same space as space the space value space of
trigonometrical space function space for space the space same space angle space in space terms space of space positive space acute space angle.
Here comma space the space angle space given space is space the space negative space angle space greater space than space 2 straight pi equals 360 degree
We space need space to space convert space minus 1710 degree space to space straight a space positive space acute space angle.
So comma space let space us space express space teh space angle space in space the space form space
straight alpha equals nπ plus-or-minus straight theta comma
where space straight theta space is space an space acute space angle.
Therefore comma
cos space left parenthesis negative 1710 degree right parenthesis equals cos left parenthesis 10 straight pi minus 1710 degree right parenthesis equals cos space left parenthesis 90 degree right parenthesis equals 0 end style

Tuesday, March 07, 2017 at 18:28:PM