cos A=4/5 , cos B= 12/13. find i)cos A+B. ii)sin A-B
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cos(A+B)= cosAcosB - sinAsinB
cosA=4/5 by pythogreas rule sinA=3/5
cosB =12/13 SinB = 5/13
cos(A+B)= 4/5* 12/13 - 3/5 * 5/13
cos(A+B)= 48/65 - 15/65
cos(A+B)= 33/65
2. sin(A-B) = SinAcosB - cosAsinB
sin(A-B)= 3/5× 12/13 - 4/5 × 5/13
sin(A-B) = 36/65 - 20/65
sin(A-B)= 16/65 is answer
cosA=4/5 by pythogreas rule sinA=3/5
cosB =12/13 SinB = 5/13
cos(A+B)= 4/5* 12/13 - 3/5 * 5/13
cos(A+B)= 48/65 - 15/65
cos(A+B)= 33/65
2. sin(A-B) = SinAcosB - cosAsinB
sin(A-B)= 3/5× 12/13 - 4/5 × 5/13
sin(A-B) = 36/65 - 20/65
sin(A-B)= 16/65 is answer
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