In a , let , , and . All symbols have their usual meanings in a…

MATHEMATICS · Multi-part · A Level · Mathematics · Trigonometry · Trigonometry

Problem

In a

\triangle ABC

, let

a=6

b=3

, and

\cos(A-B)=\frac{4}{5}

. All symbols have their usual meanings in a triangle. (1) Statement I:

\angle B=\frac{\pi}{2}

(2) Statement II:

\sin A=\frac{2}{\sqrt{5}}