simple trig function dillema (1 Viewer)

[jisu]

could someone inform me specifically as to when to use my calculator in degrees mode and when to use it in radian mode. i always get so confused.

in one trig question i did today i had to use both modes! ?=(

help ;_;

 

[acmilan]

You can use radians for all situations, but if you prefer to work with degrees then a general rule is to always use radians when doing application of calculus to the physical world. In things such as geometry, degrees is fine unless otherwise specified.

 

[Slidey]

Remember that 2pi=360 degrees, thus 1 degree = pi/180. However, I myself always use radians.

You can remember thing in degrees, like sin30=1/2, but in the end you should be writing sin(pi/6)=1/2

 

[jemsta]

you also need the radian form when youre doing the trig functions

 

[brett86]

if you prefer to work with degrees then a general rule is to always use radians when doing application of calculus

good point! 2u students often forget that they must use radians when doing anything that involves calculus

this is because in the derivation of the gradient of sin x, the gradient of sin x only equals cos x when:

which is only true when x is in radians, put ur calc into radians and try it for small x

2u students frequently make errors in this because the derivation of trig differentiation was removed after trig expansions were removed from the 2u course a long time ago

the board of studies has made many blunders...

 

[who_loves_maths]

you should remember some simple conversion formulae between radians and degrees also, just in case. ie. 'x' degrees = x*pi/180 radians ; and 'y' radians = y*180/pi degrees

and like ppl have said so far, be particularly careful of angle measure units when doing questions of the topic "applications of calculus". eg. in integrating definite integrals, or, when converting and changing ordinates of definite integrals, always use radians.