6. Find an exact value. (1 point)sin 75°a) quantity negative square root of six plus square root of two divided by four.b) quantity square root of six minus square root of two divided by four.c) quantity negative square root of six minus square root of two divided by four.d) quantity square root of six plus square root of two divided by four.7. Find an exact value. (1 point)sine of negative eleven pi divided by twelve.a) quantity square root of six plus square root of two divided by four.b) quantity negative square root of six minus square root of two divided by four.c) quantity square root of two minus square root of six divided by four.d) quantity square root of six minus square root of two divided by four.8. Write the expression as the sine, cosine, or tangent of an angle. (1 point)sin 9x cos x - cos 9x sin xa) sin 10xb) cos 8xc) sin 8xd) cos 10x9. Write the expression as the sine, cosine, or tangent of an angle. (1 point)cos 112° cos 45° + sin 112° sin 45°a) sin 157°b) sin 67°c) cos 157°d) cos 67°10. Rewrite with only sin x and cos x. (1 point)sin 2x - cos 2xa) 2 sinx cosx - 1 + 2 sin2xb) 2 sin x cos2x - 1 + 2 sin2xc) 2 sin x cos2x - sin x + 1 - 2 sin2xd) 2 sin x cos2x - 1 - 2 sin2xPLEASE HELP!

6 Find an exact value. 
sin 75°
sin(A+B)=sin(A)cos(B)+cos(A)sin(B)
sin(45)=cos(45)=(2^0.5)/2    sin(30)=0.5      cos(30)=(3^0.5)/2
sin(45+30)=sin(45)cos(30)+cos(45)sin(30)=(6^0.5+2^0.5)/4
the answer is the letter d) quantity square root of six plus square root of two divided by four.

7. Find an exact value. 
sine of negative eleven pi divided by twelve.

sin(-11pi/12) = -sin(11pi/12) = -sin(pi - pi/12) = -sin(pi/12) = -sin( (pi/6) / 2)

= - sqrt( (1-cos(pi/6) ) / 2) = -sqrt( (1-√3/2) / 2 ) = -(√3-1) / 2√2=(√2-√6)/4
the answer is the letter c) quantity square root of two minus square root of six divided by four.

8. Write the expression as the sine, cosine, or tangent of an angle. 
sin 9x cos x - cos 9x sin x
sin(A−B)=sinAcosB−cosAsinBsin(9x−x)= sin9xcosx−cos9xsinx= sin(8x)the answer is the letter c) sin 8x9. Write the expression as the sine, cosine, or tangent of an angle. 
cos 112° cos 45° + sin 112° sin 45°

cos(A−B)=cosAcosB+sinAsinBcos(112−45)=cos112cos45+sin112sin45=cos(67)the answer is the letter d) cos 67°

10. Rewrite with only sin x and cos x. sin 2x - cos 2x   sin2x = 2sinxcosx
cos2x = (cosx)^2 - (sinx)^2 = 2(cosx)^2 -1 = 1- 2(sinx)^2 sin2x- cos2x=2sinxcosx-(1- 2(sinx)^2=2sinxcosx-1+2(sinx)^2 sin2x- cos2x=2sinxcosx-1+2(sinx)^2 the answer is the letter b) 2 sin x cos2x - 1 + 2 sin2x