'PROGRAM test_cst ' Test of sine, cosine & tangent ' 1. sin(2.x) = 2.sin(x).cos(x) ' 2. cos(2.x) = (cos(x) + sin(x)).(cos(x) - sin(x)) ' 3. sec(x)^2 = 1 + tan(x)^2 #Include "quad_1x.bi" Using quad_precision #define EPSILON_HALF 2.22044604925031308E-016 Dim As quad x, twox, sine, cosine, tangent, lhs, rhs, diff Dim As Double r Dim As Integer i Screen 0 Width 104,32 Color 15,1 Cls Randomize 4711 For i = 1 To 10 x.hi=Rnd r= Rnd x.hi = (x.hi - 0.5) / r x.lo = x.hi * EPSILON_HALF ' sin(2.x) = 2.sin(x).cos(x) twox = 2.0 * x lhs = Sin(twox) sine = Sin(x) cosine = Cos(x) rhs = sine * cosine rhs = 2.0 * rhs diff = lhs - rhs Print "sin(2x) lhs ="; lhs, " Diff. ="; diff ' cos(2.x) = (cos(x) + sin(x)).(cos(x) - sin(x)) lhs = Cos(twox) rhs = (cosine + sine) * (cosine - sine) diff = lhs - rhs Print "cos(2x) lhs ="; lhs, " Diff. ="; diff ' sec(x)**2 = 1 + tan(x)**2 diff.hi = 1.0 diff.lo = 0.0 lhs = diff / cosine lhs = lhs * lhs tangent = Tan(x) rhs = diff + tangent * tangent diff = lhs - rhs Print "sec(x)^2 lhs ="; lhs, " Diff. ="; diff Next Sleep