Current location - Training Enrollment Network - Mathematics courses - Jiangsu senior high school mathematics compulsory 5
Jiangsu senior high school mathematics compulsory 5
1, according to Sina a=sinB b=sinC c? Found a: b: c = 1: 2: 3.

2. Because A+C=2B? So b = 60? According to cosine theorem b 2? =? a^2? +? c^2? -? 2 a c cosB? Found that c equals 2.

So the triangle is a right triangle? C=90? So the value of sinC is 1.

3. as shown in the figure? You know 2R=a\sinA? Similarly, other angles can also prove that Sina is a=sinB, b=sinC and c.