Answer :
Sorry I can't solve it.
Firstly, the equation is wrong. It is supposed to be 81 ≠ 30.25
Second of all, this is the best I got 81= −76 (cos(r) + 106.25
Firstly, the equation is wrong. It is supposed to be 81 ≠ 30.25
Second of all, this is the best I got 81= −76 (cos(r) + 106.25