More identities and angles Flashcards
1
Q
pythagorean identities
A
- sin^2x + cos^2x=1
- tan^2x +1 =sec^2x
- 1 + cot^2x=csc^2x
2
Q
sin(-x)
A
-sin(x)
3
Q
csc(-x)
A
-csc(x)
4
Q
tan(-x)
A
-tan(x)
5
Q
cos(-x)
A
cos(x)
6
Q
sec(-x)
A
sec(x)
7
Q
cot(-x)
A
-cot(x)
8
Q
sin20
theta
A
2sin0cos0
9
Q
cos20
theta; double - angle
A
cos^20-sin^0
10
Q
tan20
theta; double - angle
A
2tan0/1-tan20
11
Q
sin (a + B)
double - angle
A
=sin a cos B + cos a sin B
12
Q
sin(2a)
double - angle
A
=sin (0 + 0)=sin 0
13
Q
sin^20
power reduction rule
A
=1-cos20/2=1/2 (1-cos20)
14
Q
cos^20
power reduction rule
A
1+cos20/2=1/2(1+cos20)
15
Q
sin0/2
half angle
A
=-/+ sqrt (1-cos/2)
