Why when I use this calculator it says pi/4((cos(pi/16))^2+(cos(3pi/16))^2+cos(5pi/16)^2+cos(7pi/16)^2)=3.1408 but the actual answer is 1.5708?
You have the calculator set to "degree" mode......change it to "radian" mode [at the bottom left] and you should get the correct result
lolz !
thank you Alfred E Neuman :)
