15.(2022秋•西昌市期末)(1)在ΔABC\Delta ABCΔABC中已知cosA=−513\cos A=-\frac{5}{13}cosA=−135,求sinA\sin AsinA,tanA\tan AtanA的值;(2)在ΔABC\Delta ABCΔABC中已知cosB+sinB=15\cos B+\sin B=\frac{1}{5}cosB+sinB=51,求sinB⋅cosB\sin B\cdot \cos BsinB⋅cosB的值.