Trigonometric Identities
cot(-x) = ?
-cot(x)
If sinx = 28/53, cotx = ?
45/28 (draw a triangle!)
cos(a-b) = ?
cos(a)cos(b) + sin(a)sin(b)
sec(90°-x) = ?
csc(x)
cos(90°-x) = ?
sin(x)
cot(90°-x) = ?
tan(x)
csc(-x) = ?
-csc(x)
tan(-x) = ?
-tan(x)
csc²x - cot²x = ?
1
Simplify sin(-x)cos(-x)tan(-x)
sin²x
2sin(x)cos(x) = ?
sin(2x)
sin(a+b) = ?
sin(a)cos(b) + cos(a)sin(b)
sin(a-b) = ?
sin(a)cos(b) - cos(a)sin(b)
sin(2x) = ?
2sin(x)cos(x)
tan(2x) = ?
2tan(x)/[1-tan²(x)]
Expand sin(4x) Hint: rewrite as sin(2(2x))
4sin(x)cos³(x) - 4sin³(x)cos(x)
Determine whether the following is true: csc(x)sec(x) = [2]/[sin(2x)]
True
tan(a-b) = ?
[tan(a)-tan(b)]/[1+tan(a)tan(b)]
Simplify cscx(sinx + cos(x)cot(x))
csc²x
Simplify [1]/[cos²x] - [1-cos(2x)]/[1+cos(2x)]
1
sin²x = ? (Half Angle Identity)
[1 - cos(2x)]/2
1 - 2sin²x
cos(2x)
tan²x + 1 = ?
sec²x
tan(a+b) = ?
[tan(a)+tan(b)]/[1−tan(a)tan(b)]
cos²x = ? (Half Angle Identity)
[1+cos(2x)]/2
tan²x (Half Angle Identity)
[1-cos(2x)]/[1+cos(2x)]
Give the exact value of cos(105°) using the sum identity for cosine.
[√2 - √6]/[4] If your answer looks different, try simplifying (or enter your answer into your calculator and see if the decimal matches -0.258819).
Find sin(2*π/3) using the double angle formula.
[√3]/[2]
2cos²x - 1
cos(2x)
cos²x - sin²x = ?
cos(2x)
cos(a+b) = ?
cos(a)cos(b) - sin(a)sin(b)
cos(-x) = ?
cos(x)
sin(90°-x) = ?
cos(x)
cotx in terms of sinx and cosx
cosx/sinx
1 - sin²x = ?
cos²x
cos(2x) = ?
cos²x - sin²x 2cos²x - 1 1 - 2sin²x
tan(90°-x) = ?
cot(x)
Simplify [2cosx]/[1-cos(2x)]
csc(x)cot(x) OR [1/sinx]*[cosx/sinx]
1 + cot²x = ?
csc²x
Simplify [cos²x - sin²x]/[1-cos²x]
csc²x - 2
csc(90°-x) = ?
sec(x)
sec(-x) = ?
sec(x)
Simplify sin²x + cos²x + tan²x
sec²x
sin(-x) = ?
sin(x)
tanx in terms of sinx and cosx
sinx/cosx
1 - cos²x = ?
sin²x
sec²x - tan²x = ?
1
sin²x+cos²x = ?
1
Find the exact value of the expression: sin(60°)cos(30°) + cos(60°)sin(30°)
1 (Using the sum identity for sine, you will also see that the expression equals sin(90°), which is also equal to 1.
Find the exact value of tan(75°) using the sum identity.
2 + √3
