Question

Solve for x.cos(2x+9)=sin(x)

Answer 1

x=27

Explanation:

cos and sin are complementary angles. There theta or x add up to 90 degree. Using the formula.

cos x=sin y where x+y=90 let set up the equation.

`\cos(2x + 9) = \sin(x)`

`2x + 9 + x = 90`

`3x + 9 = 90`

`3x = 81`

`x = 27`

To check our identity plug x in the top equation

`\cos(2 * 27 + 9)) = \sin(27)`

`\cos(63) = \sin(27)`

they both equal about 0.45 so it is true.

x=27