Espes your answer n theftom cos255 for some numbers a and

, Espes your answer n theftom cos(255*) = for some numbers a and b. 4 a= help (numbers) help (numbers)

Solution

cos(x+y)=cosxcosy-sinxsiny
cos 255=cos(210+45)=(cos210*cos45-sin210*sin45)

cos 210º = cos 30º = -3/2 in quadrant III where cos is negative

sin 210º = sin 30º = -1/2 in quadrant III where sin is also negative
cos(x+y) = (-3/2*2/2) - (-1/2*2/2)
cos(x+y) = (-6/4) - (-2/4)
cos(x+y) = (-6 + 2)/4 = 2(1 - 3)/4

a = 2

b = 3