how would you express cos(75 as a single fraction?

1 answer

im assuming oyu saying cos75 degree as a simple fraction;

cos(75)=cos(45+30)
recall the formula cos(a+b)=cos a cosb-
sin a sin b

cos(45+30)=cos(30)sin(45)-
sin(30)sin(45)

cos(45+30)=((sqrt(3))/2)((sqrt(2))/2)-…

cos(45+30)
=(sqrt(6)- sqrt(2))/4