M115 54 X W Practice webassign net webstudert Assignment Res

M115 5.4 X W Practice webassign net webstudert Assignment Responses submit?depe 1647729 | 18.-/1 points LarPCalc1054033. Write the expression as the sine, cosine, or tangent of an angle. cos 3x cos 2y + sin 3x sin 2y Need Help? Eeean- ad It 15.--r1 ports LarpCaic10 S 4,035. Find the exact value of the expression. sincos,cos- sing 42 Need Help? Read I 20. -1 points LarPCalc 10 5.4.033 Find the exact value of the expression. sin(120°) cos(75)-cos(120°) sin(75°) Read n Search the web and Windows Th

Solution

18. We know that (cos a*cos b) + (sin a* sinb) = cos(a-b)

Put a=3x and b=2y , we get

Cos3x cos2y+ sin3x sin2y = cos (3x-2y)