trig Flashcards
1
Q
sin(a-b)
A
sin(a)cos(b)-sin(b)cos(a)
2
Q
sin(a+b)
A
sin(a)cos(b)+sin(b)cos(a)
3
Q
cos(a-b)
A
cos(a)cos(b)+sin(a)sin(b)
4
Q
cos(a+b)
A
cos(a)cos(b)-sin(a)sin(b)
5
Q
tan(a-b)
A
(tan(a)-tan(b))/(1+tan(a)*tan(b))
6
Q
in what situations is tan(a-b) used
A
to find w (angle between 2 lines)
7
Q
sin(2a)
A
2sin(a)*cos(a)
8
Q
cos(2a)
A
cos^2(a) - sin^2(a)
9
Q
pythagorean theorem for sin and cos
A
cos^2(a)+sin^2(a)=1
10
Q
how do you find a line alpha angle (a) when you have angle of inclination (x)
A
when angle of inclination (x) is greater than 90, find it through tan inverse of the slope and then subtract that from 180
11
Q
what is sin inverse D and R
A
D: [-1,1] R: [-pi/2,pi/2]
12
Q
what is cosine inverse D and R
A
D: [-1,1] R: [0,pi]
13
Q
what is tan inverse D and R
A
D: all real R:[-pi/2,pi/2]
14
Q
sin(-x)=?
A
-sin(x)
15
Q
cos(-x)=?
A
cos(x)
