BAYANA SAGAR
Last Activity: 11 Years ago
COS(A-B)=COSA.COSB+SINA.SINB
1.COS(A-B)
Let X`OX AND YOY` be the coordinate axes.Consider a unit circle with O as the centre.
Let p1,p2 and p3 be the three points on the circle such that angleXOP1=A,angleXOP2=B and angle XOP3=A-B.
As we know that the terminal side of any angle intersects the circle with centre at O and unit radius at a point whose coordinates are the cosine and sine of angle.
Chordp0p3=Chordp1p2