Trig Identities

Question 1

quotient identity tan thaeta =

Answer 1

sine thaeta divided by cosine thaeta

Question 2

quotient identity cotangent thaeta =

Answer 2

cosine thaeta divided by sine thaeta

Question 3

reciprocal identity sine thaeta =

Answer 3

1 divided by cosecant

Question 4

reciprocal identity cosine thaeta =

Answer 4

1 divided by secant thaeta

Question 5

reciprocal identity tangent thaeta =

Answer 5

1 divided by cotangent thaeta

Question 6

reciprocal identity cosecant thaeta =

Answer 6

1 divided by sine thaeta

Question 7

reciprocal identity secant thaeta =

Answer 7

1 divided by cosine thaeta

Question 8

reciprocal identity cotangent thaeta =

Answer 8

1 divided by tangent thaeta

Question 9

Pythagorean identity sin^2•€+cos^2€

Answer 9

=1

Question 10

Pythagorean identity tan€^2+1

Answer 10

=sec€^2

Question 11

1+cot^2€

Answer 11

=csc^2€

Question 12

addition formula sin(€,1+/- €,2)

Answer 12

sin€,1cos€,2+/-sin€,2cos€,1

Question 13

addition formula cos(€,1+/-€,2)

Answer 13

cos€,1cos€,2+/-sin€,1sin€,2

Question 14

double angle formula sin2€

Answer 14

=2sin€cos€

Question 15

double angle formula cos2€

Answer 15

cos^2€-sin^2€=2cos^2€-1=1-2sin^2€

Question 16

double angle formula tan2€

Answer 16

=2tan€/1-tan^2€

Question 17

half angle formula cos^2€

Answer 17

=1+cos2€/2

Question 18

half angle formula sin^2€

Answer 18

=1-cos2€/2