| sin(x) = cos(90-x) | הזהויות היסודיות |
| tan(x) = cot(90-x) |
| tan(x) = sin(x)/cos(x) |
| cot(x) = cos(x)/sin(x) |
| (sin(x))^2+(cos(x))^2 = 1 |
| tan(x)cot(x) = 1 |
| 1+(tan(x))^2 = 1/(cos(x))^2 |
| 1+(cot(x))^2 = 1/(sin(x))^2 |
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| sin(x+y) = sin(x)cos(y)+sin(y)cos(x) | סכום והפרש זויות |
| sin(x-y) = sin(x)cos(y)-sin(y)cos(x) |
| cos(x+y) = cos(x)cos(y)-sin(x)sin(y) |
| cos(x-y) = cos(x)cos(y)+sin(x)sin(y) |
| tan(x+y) = [tan(x)+tan(y)]/[1-tan(x)tan(y)] |
| tan(x-y) = [tan(x)-tan(y)]/[1+tan(x)tan(y)] |
| cot(x+y) = [cot(y)cot(x)-1]/[cot(y)+cot(x)] |
| cot(x-y) = [cot(y)cot(x)+1]/[cot(y)-cot(x)] |
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| sin(2x) = 2sin(x)cos(x) | זוית כפולה |
| cos(2x) = (cos(x))^2-(sin(x))^2 = 2(cos(x))^2-1 = 1-2(sin(x))^2 |
| tan(2x) = 2tan(x)/[1-(tan(x))^2] |
| cot(2x) = [(cot(x))^2-1]/2cot(x) |
| sin(2x) = 2tan(x)/[1+(tan(x))^2] = 2cot(x)/[1+(cot(x)^2] |
| cos(2x) = [1-(tan(x))^2]/[1+(tan(x))^2] = [(cot(x))^2-1]/[(cot(x))^2+1] |
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| sin(3x) = 3sin(x)-4(sin(x))^3 = sin(x)[2cos(x)+1][2cos(x)-1] | זוית משולשת |
| cos(3x) = 4(cos(x))^3-3cos(x) = cos(x)[1+2sin(x)][1-2sin(x)] |
| tan(3x) = [3tan(x)-(tan(x)^3]/[1-3(tan(x)^2] |
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| sin(x)+sin(y) = 2sin((x+y)/2)cos((x-y)/2) | סכום והפרש פונקציות |
| sin(x)-sin(y) = 2sin((x-y)/2)cos((x+y)/2) |
| cos(x+y) = 2cos((x+y)/2)cos((x-y)/2) |
| cos(x-y) = 2sin((x+y)/2)sin((x-y)/2) |
| tan(x)+tan(y) = sin(x+y)/cos(x)cos(y) |
| cot(x)+cot(y) = sin(y+x)/sin(x)sin(y) |
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| sin(x)cos(y) = 0.5[sin(x+y)+sin(x-y)] | מכפלת פונקציות |
| cos(x)sin(y) = 0.5[sin(x+y)-sin(x-y)] |
| cos(x)cos(y) = 0.5[cos(x-y)+cos(x+y)] |
| sin(x)sin(y) = 0.5[cos(x-y)-cos(x+y)] |
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| (sin(x))^2-(sin(y))^2 = (cos(y))^2-(cos(x))^2 = sin(x+y)sin(x-y) | הפרש וסכום ריבועים |
| (cos(x))^2-(sin(y))^2 = (cos(y))^2-(sin(x))^2 = cos(x+y)cos(x-y) |
| (sin(x))^2+(sin(y))^2 = 1-cos(x+y)cos(x-y) |
| (cos(x))^2+(cos(y))^2 = 1+cos(x+y)cos(x-y) |
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| a/sin(x)+b/sin(y)+c/sin(z) = 2R | משפט הסינוסים |
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| c^2 = a^2+b^2-2abcos(z) | משפט הקוסינוסים |
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| S = absin(z)/2 | שטח משולש |
| S = [sin(y)sin(z)a^2]/[2sin(x)] |
| S = 2R^2sin(x)sin(y)sin(z) |