TAN - QB64 Wiki

TAN

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The TAN function returns the ratio of SINe to COSine or tangent value of an angle measured in radians.


Syntax:

tangent! = TAN(radian_angle!)


Parameters:

  • The radian_angle must be measured in radians.


Description:

  • To convert from degrees to radians, multiply degrees * π/180.
  • 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 errors.


Example: Spiraling text using the SIN and TAN functions.

DIM SHARED text AS STRING text$ = "S P I R A L" DIM SHARED word(1 TO LEN(text$) * 8, 1 TO 16) CALL analyse CLS CALL redraw SUB analyse CLS SCREEN 12 COLOR 2: LOCATE 1, 1: PRINT text$ DIM px AS INTEGER, py AS INTEGER, cnt AS INTEGER, ltrcnt AS INTEGER px = 1: py = 1 DO word(px, py) = POINT(px, py) PSET (px, py), 1 px = px + 1 IF px = LEN(text$) * 8 THEN px = 1 py = py + 1 END IF LOOP UNTIL py = 16 END SUB SUB redraw CLS DIM row AS INTEGER, cnt AS INTEGER, cstart AS SINGLE, cend AS SINGLE DIM xrot AS INTEGER, yrot AS INTEGER, SCALE AS INTEGER, pan AS INTEGER cstart = 0: cend = 6.2 xrot = 6: yrot = 6: SCALE = 3: pan = 30 OUT &H3C8, 1: OUT &H3C9, 10: OUT &H3C9, 10: OUT &H3C9, 60 DO row = 2 DO DO FOR i = cend TO cstart STEP -.03 x = (SCALE * 60 - (row * xrot / 4)) * TAN(COS(i)) y = SIN(SCALE * 60 - (row * yrot)) * TAN(SIN(i)) * pan cnt = cnt + 1 IF word(cnt, row) > 0 THEN CIRCLE (x + 320, y + 220), SCALE + 1, 1 'circled letters 'LINE (x + 320, y + 220)-STEP(12, 12), 1, BF 'boxed letters END IF IF cnt = LEN(text$) * 8 THEN cnt = 0: EXIT DO NEXT LOOP row = row + 1 LOOP UNTIL row = 16 cend = cend + .1 cstart = cstart + .1 now! = TIMER DO newnow! = TIMER LOOP UNTIL newnow! - now! >= .15 LINE (1, 100)-(639, 280), 0, BF LOOP UNTIL INKEY$ = CHR$(27) END SUB

Code by Unseen Machine


See also:



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