B
blackrose713


giúp mình nhé:
1. Cotx + sinx[1+tan(x/2)tanx] = 4
2. Tan^2x + cot^2x + cot^2(2x) = 11/3
3. Cotx – 1 = 2sin[(pi/4)-x](tanx + cot2x)
1. Cotx + sinx[1+tan(x/2)tanx] = 4
2. Tan^2x + cot^2x + cot^2(2x) = 11/3
3. Cotx – 1 = 2sin[(pi/4)-x](tanx + cot2x)