sinC = sin90 = 1

cosC = cos90 = 0

sinA = 7/25

cosA = 24/25

tanA = 7/24

cotA = 24/7

1. K2CO3: Muối

2. CuO: Oxit bazơ

3. SO2: Oxit axit

4. H2SO4: axit có nhiều oxi

5. Mg(NO3)2: muối

6. NaOH: bazơ

7. H2S: axit không có oxi

8. P2O5: oxit axit

9. MgCl2: muối

10. Fe2O3: oxit bazơ

11. H2SO3: axit có ít oxi

12. Ca2(PO4)3: muối

13. Fe(OH)3: bazơ

14. Pb(NO3)2: muối

15. BaSO4: muối

5

Bài 6:

a) m-2=0 <=> m = 2

b) Góc nhọn: 1-4m>0

<=> m < 1/4

Góc tù: m > 1/4

c) m - 2 = 3/2 <=> m = 7/2

9. The dog is not playing with a ball.

10. Why is it raining now?

11. How is she travelling?

12. Where are you working?

13. You're meeting your friend at four.

14. Am I taking too much cake?

2. They're working now.

3. You're not walking.

4. Are they learning new things?

5. When is he starting work?

6. Why am I staying at home?

7. Is it getting dark?

8. We're not winning.

@Minh Lệ Ngọc: oke