Without using calculator, find the value of the following Cos 75 , Sin Sin . Cos Tan 105 12 12

Q: Use reference angles to find the exact value of the expression cos 23π/4. Do not use a calculator.

A:

Q: Use reference angles to find the exact value of the expression cos 3π/4. Do not use a calculator.

A: The given angle is in second quadrant, and the value of cosine is negative in second quadrant.

Q: Cannot solve

A: cos-1(cos(π/8)) We know, cos-1(cos(x)) = x

Q: True or False sin 52° = cos 48°.

A: Given: sin 52°=cos 48° To Find: To check the given statement for True or False.

Q: sin 25° tan 65° tan 25° cos 65° -

A:

Q: Find the exact value of the expression cos 240°.Do not use a calculator.

A: It is known that cosx+y=cosxcosy-sinxsiny and cos180∘ =-1, sin180∘ =0, cos60∘ =12, sin60∘ =32.