- #1
will.i.am2
- 14
- 0
Verify the compound angle formulae for;
a) sin (20° + 30°)
sin(A + B) = sinAcosB + cosAsinB
sin(20°+30°) = (sin20°)(cos30°) + (cos20°)(sin30°)
0.76 = (0.34 x 0.87) + (0.94 x 0.5)
0.76 = 0.29+0.47
0.76 = 0.76
b) cos (30° + 40°)
cos(A + B) = cosAcosB - sinAsinB
cos(30°+40°) = (cos30°)(cos40°) - (sin30°)(sin40°)
0.34 = 0.87 x 0.77 - 0.5 x 0.64
0.34 = 0.67 - 0.32
0.34 = 0.35
Can someone please verify these answer for me? as I am not good in maths so I just wanted make sure if i had done it right or do I need any changes?
a) sin (20° + 30°)
sin(A + B) = sinAcosB + cosAsinB
sin(20°+30°) = (sin20°)(cos30°) + (cos20°)(sin30°)
0.76 = (0.34 x 0.87) + (0.94 x 0.5)
0.76 = 0.29+0.47
0.76 = 0.76
b) cos (30° + 40°)
cos(A + B) = cosAcosB - sinAsinB
cos(30°+40°) = (cos30°)(cos40°) - (sin30°)(sin40°)
0.34 = 0.87 x 0.77 - 0.5 x 0.64
0.34 = 0.67 - 0.32
0.34 = 0.35
Can someone please verify these answer for me? as I am not good in maths so I just wanted make sure if i had done it right or do I need any changes?