Suppose 𝐴 is in Quadrant III and 𝐵 is in Quadrant I. If cos(𝐴)=−40/41 and sin(𝐵)=15/17 , then cos(𝐴−𝐵)=

Question

Suppose 𝐴   is in Quadrant III and 𝐵   is in Quadrant I. If cos(𝐴)=−40/41 and sin(𝐵)=15/17 , then cos(𝐴−𝐵)=

Raymond B. · Accepted Answer

cos(A-B) = cosAcosB + sinAsinB= -40/41(8/17) + (-8/17)(15/17)

1 Expert Answer