Trigonometry (4)

Question 1

What is sin(A+-B)

Answer 1

sinAcosB +- cosAsinB

Question 2

sinAcosB +- cosAsinB

Answer 2

What is sin(A+=B)

Question 3

What is cos(A+-B)?

Answer 3

sinAsinB -+ cosAcosB

Question 4

sinAsinB -+ cosAcosB

Answer 4

What is cos(A+-B)?

Question 5

What is tan(A+-B)?

Answer 5

(tanA+-tanB)/(1-+tanAtanB)

Question 6

(tanA+-tanB)/(1-+tanAtanB)

Answer 6

What is tan(A+-B)?

Question 7

What is sin 2A?

Answer 7

2 sin A cos A

Question 8

2 sin A cos A

Answer 8

What is sin 2A?

Question 9

What is cos 2A?

Answer 9

cos^2 A - sin^2 A
2 cos^2 A - 1
1 - 2 sin^2 A

Question 10

cos^2 A - sin^2 A
2 cos^2 A - 1
1 - 2 sin^2 A

Answer 10

What is cos 2A?

Question 11

What is tan 2A?

Answer 11

(2 tan A)/(1 - tan^2 A)

Question 12

(2 tan A)/(1 - tan^2 A)

Answer 12

What is tan 2A?

Question 13

What is (cos^2pheta/cos^2pheta) + (sin^2pheta/cos^2pheta)?

Answer 13

1/cos^2pheta

Question 14

1/cos^2pheta

Answer 14

What is (cos^2pheta/cos^2pheta) + (sin^2pheta/cos^2pheta) divided by cos^2pheta?

Question 15

What is (cos^2pheta/sin^2pheta) + (sin^2pheta/sin^2pheta)?

Answer 15

1/sin^2pheta

Question 16

1/sin^2pheta

Answer 16

What is (cos^2pheta/sin^2pheta) + (sin^2pheta/sin^2pheta)?

Question 17

Solve 4sinx + 5cosx = 0

Answer 17

(4sinx/cosx) + (5cosx/cosx) = 0
4tanx + 5 = 0
4tanx = -5
tanx = -5/4

Question 18

Solve sin(x-35degrees) = cosx

Answer 18

cos(x - 125) = cosx
x - 125 = -x
2x = 125
x = 62.5
x + 180 = 242.5
{62.5, 242.5}

Question 19

Solve cos(x+60degrees) = sinx

Answer 19

cos(x+60) = cos(-x+90)
x+60 = -x+90
2x = 30
x = 15
x + 180 = 195
{15, 195}

Question 20

What’s another way of writing sin^2x

Answer 20

(1/2)(1 - cos 2x)

Question 21

(1/2)(1 - cos 2x)

Answer 21

What’s another way of writing sin^2x

Question 22

What’s another way of writing (cos^2)5x

Answer 22

(1/2)(cos10x + 1)