Question

The exact value of cos5pi/12 is:​

Answer 1

Step 1: Convert
`(5\pi )/(12)`, which is in radians into degrees. To convert it multiply by
`(180)/(\pi )`

`(5\pi )/(12) =(180)/(\pi )`

900/12

75

Step 2: 75 degrees isn't on the unit circle but 45 degrees and 30 degrees is. Since 45 + 30 = 75 you can use the cosine of 45 and 30 to find the exact value

cos45 =
`(√(2) )/(2)`

cos30 =
`(√(3) )/(2)`

Step 3: Add the cos45 and cos30 to get cos5pi/12

`(√(2) )/(2) +(√(3) )/(2) = (√(2)+√(3))/(2)`

Hope this helped!

Answer 2

Answer: on ap3x it is sqrt 2(sqrt3 -1)/4

Step-by-step explanation: yw