33 lines
845 B
C
33 lines
845 B
C
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#include <math.h>
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float cosf(float x) {
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float pi = M_PI;
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int temp;
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float deg_2, deg_4, deg_6, deg_8, deg_10;
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float deg_12, deg_14, deg_16, deg_18, deg_20;
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float cosine;
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if(x < 0) x = -x;
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if(x >= 2 * pi || x <= -2 * pi) {
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temp = x / (2 * pi);
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x -= temp * (2 * pi);
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}
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deg_2 = (x - pi) * (x - pi) / 2;
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deg_4 = deg_2 * deg_2 * 2 / (4 * 3);
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deg_6 = deg_4 * deg_2 * 2 / (6 * 5);
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deg_8 = deg_6 * deg_2 * 2 / (8 * 7);
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deg_10 = deg_8 * deg_2 * 2 / (10 * 9);
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deg_12 = deg_10 * deg_2 * 2 / (12 * 11);
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deg_14 = deg_12 * deg_2 * 2 / (14 * 13);
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deg_16 = deg_14 * deg_2 * 2 / (16 * 15);
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deg_18 = deg_16 * deg_2 * 2 / (18 * 17);
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deg_20 = deg_18 * deg_2 * 2 / (20 * 19);
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cosine = -1 + deg_2 - deg_4 + deg_6 - deg_8 + deg_10;
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cosine = cosine - deg_12 + deg_14 - deg_16 + deg_18 + deg_20;
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return cosine;
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}
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