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92 lines
3 KiB
Plaintext
92 lines
3 KiB
Plaintext
The [[TAN]] function returns the ratio of [[SIN]]e to [[COS]]ine or tangent value of an angle measured in radians.
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{{PageSyntax}}
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::: tangent! = '''TAN('''''radian_angle!''''')'''
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{{Parameters}}
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* The ''radian_angle'' must be measured in radians.
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{{PageDescription}}
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* To convert from degrees to radians, multiply degrees * π/180.
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* TANGENT is the gradient or slope of the circle or arc at [[SIN]](θ) / [[COS]](θ). Do not use division when the [[COS]] = 0 to avoid [[ERROR Codes|errors]].
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''Example:'' Spiraling text using the [[SIN]] and [[TAN]] functions.
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{{CodeStart}} '' ''
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{{Cl|DIM}} {{Cl|SHARED}} text {{Cl|AS}} {{Cl|STRING}}
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text$ = "S P I R A L"
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{{Cl|DIM}} {{Cl|SHARED}} word(1 {{Cl|TO}} {{Cl|LEN}}(text$) * 8, 1 {{Cl|TO}} 16)
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{{Cl|CALL}} analyse
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{{Cl|CLS}}
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{{Cl|CALL}} redraw
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{{Cl|SUB}} analyse
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{{Cl|CLS}}
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{{Cl|SCREEN}} 12
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{{Cl|COLOR}} 2: {{Cl|LOCATE}} 1, 1: {{Cl|PRINT}} text$
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{{Cl|DIM}} px {{Cl|AS}} {{Cl|INTEGER}}, py {{Cl|AS}} {{Cl|INTEGER}}, cnt {{Cl|AS}} {{Cl|INTEGER}}, ltrcnt {{Cl|AS}} {{Cl|INTEGER}}
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px = 1: py = 1
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DO
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word(px, py) = {{Cl|POINT}}(px, py)
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{{Cl|PSET}} (px, py), 1
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px = px + 1
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{{Cl|IF...THEN|IF}} px = {{Cl|LEN}}(text$) * 8 {{Cl|THEN}}
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px = 1
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py = py + 1
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{{Cl|END IF}}
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{{Cl|LOOP}} {{Cl|UNTIL}} py = 16
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{{Cl|END SUB}}
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{{Cl|SUB}} redraw
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{{Cl|CLS}}
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{{Cl|DIM}} row {{Cl|AS}} {{Cl|INTEGER}}, cnt {{Cl|AS}} {{Cl|INTEGER}}, cstart {{Cl|AS}} {{Cl|SINGLE}}, cend {{Cl|AS}} {{Cl|SINGLE}}
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{{Cl|DIM}} xrot {{Cl|AS}} {{Cl|INTEGER}}, yrot {{Cl|AS}} {{Cl|INTEGER}}, SCALE {{Cl|AS}} {{Cl|INTEGER}}, pan {{Cl|AS}} {{Cl|INTEGER}}
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cstart = 0: cend = 6.2
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xrot = 6: yrot = 6: SCALE = 3: pan = 30
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{{Cl|OUT}} {{Cl|&H}}3C8, 1: {{Cl|OUT}} {{Cl|&H}}3C9, 10: {{Cl|OUT}} {{Cl|&H}}3C9, 10: {{Cl|OUT}} {{Cl|&H}}3C9, 60
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DO
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row = 2
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DO
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DO
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{{Cl|FOR...NEXT|FOR}} i = cend {{Cl|TO}} cstart {{Cl|STEP}} -.03
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x = (SCALE * 60 - (row * xrot / 4)) * {{Cl|TAN}}({{Cl|COS}}(i))
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y = {{Cl|SIN}}(SCALE * 60 - (row * yrot)) * {{Cl|TAN}}({{Cl|SIN}}(i)) * pan
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cnt = cnt + 1
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{{Cl|IF...THEN|IF}} word(cnt, row) > 0 {{Cl|THEN}}
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{{Cl|CIRCLE}} (x + 320, y + 220), SCALE + 1, 1 'circled letters
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'{{Cl|LINE}} (x + 320, y + 220)-{{Cl|STEP}}(12, 12), 1, BF 'boxed letters
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{{Cl|END IF}}
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{{Cl|IF...THEN|IF}} cnt = {{Cl|LEN}}(text$) * 8 {{Cl|THEN}} cnt = 0: {{Cl|EXIT DO}}
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{{Cl|NEXT}}
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{{Cl|LOOP}}
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row = row + 1
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{{Cl|LOOP}} {{Cl|UNTIL}} row = 16
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cend = cend + .1
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cstart = cstart + .1
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now! = {{Cl|TIMER}}
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DO
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newnow! = {{Cl|TIMER}}
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{{Cl|LOOP}} {{Cl|UNTIL}} newnow! - now! >= .15
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{{Cl|LINE}} (1, 100)-(639, 280), 0, BF
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{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} = {{Cl|CHR$}}(27)
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{{Cl|END SUB}} '' ''
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{{CodeEnd}}
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{{small|Code by Unseen Machine}}
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{{PageSeeAlso}}
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* [[_PI]] {{text|(QB64 function)}}
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* [[SIN]], [[COS]]
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* [[ATN]] {{text|(arctangent)}}
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* [[Mathematical Operations]]
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* [[Text Using Graphics]]
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* [[Mathematical_Operations#Derived_Mathematical_Functions|Derived Mathematical Functions]]
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{{PageNavigation}}
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