// Plots the sine (in red) and cosine (in green), // and tangent (in blue) with text. GRAPH LANDSCAPE, VSCALE=2.1/7.5, VOFFSET=1.05 // (don't auto-scale vertically, since tangent gets huge) PLOT COLOR=(255,0,0) // Starts a new plot - red FOR angle = 0 TO 4 * PI + .1 STEP .1 PLOT X=angle, Y=SIN(angle) // plots the Sine NEXT PLOT COLOR=(0,255,0) // starts a new plot - green FOR angle = 0 TO 4 * PI + .1 STEP .1 PLOT X=angle, Y=COS(angle) // plots the Cosine NEXT PLOT COLOR=(0,0,255) // starts a new plot - blue // Note- the tangent is discontinuous at multiples of pi/2. // We will plot the function in periods of pi. // At the discontinuities, we will stop the plot just a tiny // fraction before and resume a tiny fraction after the // discontinuity to avoid going infinite. FOR period = 0 TO 3 start_angle = period * PI angle_90 = start_angle + PI / 2 end_angle = start_angle + PI FOR angle = start_angle TO angle_90 - 1e-15 STEP .1 PLOT X = angle, Y = TAN (angle) NEXT PLOT X=angle_90 - 1e-15, Y=tan (angle_90 - 1e-15) PLOT X=angle_90 + 1e-15, Y=tan (angle_90 + 1e-15) FOR angle = angle_90 + 1e-15 TO end_angle STEP .1 PLOT X = angle, Y = TAN (angle) NEXT PLOT X = end_angle, y = TAN (end_angle) NEXT // Now put some titles on the graph. v$ = "Value of Function" TEXT YAXIS, STRING=v$ a$ = "Angle in Radians" TEXT XAXIS, STRING=a$, COLOR=(0,0,255) // blue s$="Sine" TEXT STRING=s$, COLOR=(255,0,0), X=3, Y=.55 c$="Cosine" TEXT STRING=C$, COLOR=(0,255,0), X=1.6, Y=-.65 t$="Tangent" TEXT STRING=T$, COLOR=(0,0,255), X=4.2, Y=.4 title$="Sine, Cosine\nand Tangent" // 2-line title TEXT STRING=title$, H=45, COLOR=(0,150,150), BOXED, SIZE=24