sinAsinB |
cosAcosB |
sinAsinC |
cosAcosC |
sinBsinC |
cosBcosC |
sinAsinB |
sinC |
sin(A+B) |
cosC |
即
sinAsinBcosC |
sin2C |
abcosC |
c2 |
a2+b2−c2 |
2c2 |
a2+b2 |
c2 |
故答案为:3.
a2+b2 |
c2 |
sinAsinB |
cosAcosB |
sinAsinC |
cosAcosC |
sinBsinC |
cosBcosC |
sinAsinB |
sinC |
sin(A+B) |
cosC |
sinAsinBcosC |
sin2C |
abcosC |
c2 |
a2+b2−c2 |
2c2 |
a2+b2 |
c2 |