tan (90° + 4) = cot A; sec (90° + 4) = −√cot A + 1;

:; cos (90° + A) –

5. sin Asin A; cos A = ±√1 - sin2 A; tan A = ±

14. 45°; 135°; 225°; 315°. 15. 45°; 135°. 16. 30°; 330°. 17. 30°; 150°. 18.60°; ± 120°; ± 240°; ± 300°.

21. nπ; 2 no + (2n+1)* −

1. 3.55169; .87251; 3.63548.

3. 2.65920; 2.54926; 3.85941.

2. 4.93662; 1.98320; 3.54654. 4. 6.83181; 7.51129.

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