Title Bài 1.5_Phương trình lượng giác cơ bản_CTST_Vở bài tập.pdf ✅

Chú ý: cot  cot    180 ,     x a x a k k  . 6. Giải phương trình lượng giác bằng máy tính cầm tay Ta có thể giải phương trình lượng giác dạng sinx  m,cosx  m, tanx  m và cotx  m bằng máy tính cầm tay.s Để giải phương trình cotx  aa  0 bằng MTCT, ta đưa về giải phương trình 1 tanx a  . B. CÁC VÍ DỤ RÈN LUYỆN KĨ NĂNG Ví dụ 1. Giải các phương trình a) cos 2x 0 6          ; b) cos 4x 1 3          ; c) cos x 1 5           ; d) sin 3x 0 3          e) x sin 1 2 4          ; f) sin 2x 1 6           ; Lời giải ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... Ví dụ 2. Giải phương trình a)   1 sin3x 1 2  ; b)   1 cos 2x 2 2   c)     x tan 2 3 ; d) cot 2x 3 4 3 4           Lời giải ......................................................................................................................................................................................... ......................................................................................................................................................................................... .........................................................................................................................................................................................
......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... Ví dụ 3. Giải phương trình a) sin 4x sin x 3          ; b)     0 x cot g x 30 cot g . 2 2 3 2 c) cos x ; d) sin 2x cos3x. 4    Lời giải ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... Ví dụ 4. Tìm m để phương trình 2 sin x m 4          có nghiệm x 0; 2        Lời giải ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... Ví dụ 5. Giải các phương trình sau: Lời giải ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... ......................................................................................................................................................................................... Ví dụ 6. Giải phương trình a) sin 2x  sin 2x cos x  0 1; b) sin x cos 2x  sin 2x cos3x 2.