Trig Identities

Question 1

sin2x

Answer 1

2sinxcosx

Question 2

cos2x

Answer 2

cos²x - sin²x

Question 3

cos2x

Answer 3

2cos²x - 1

Question 4

cos2x

Answer 4

1 - 2sin²x

Question 5

tan2x

Answer 5

2tanx
1 - tan²x

Question 6

1 + tan²x

Answer 6

sec²x

Question 7

1 + cot²x

Answer 7

cosec²x

Question 8

Convert degrees to radians

Answer 8

Multiply by π
180

Question 9

Radians to degreees

Answer 9

Multiply by 180
π

Question 10

Solutions for ( sinx = a ) in degrees

Answer 10

First solution: arcsin(a)
Second solution: 180 - fs
Other solutions: +/- 360 to any

Question 11

Solutions for ( sinx = a ) in radians

Answer 11

First solution: arcsin(a)
Second solution: π - first sol
Other solutions: +/- (2 π ) to any

Question 12

Solutions for (cosx = a) in degrees

Answer 12

First solution: arccos(a)
Second solution: 360 - fs
Other solutions: +/- 360 to any

Question 13

Solutions for (cosx=a) in radians

Answer 13

First solution: arccos(a)
Second solution: (2 π) - fs
Other solutions: +/- (2 π) to any

Question 14

Solutions for (tanx = a) in degrees

Answer 14

First solution: arctan(a)
Other solutions: +/- 180 to any

Question 15

Solutions for (tanx = a) in radians

Answer 15

First solution: arctan(a)
Other solutions: +/- π to any