Find the area with equtions

It's my way to find area, but there's an error ' Undefined function or variable 'x'. what's your idea?

 x0 = pi / 2 - 1 ; 
 x1 = 0.8317 ; 
 x2 = pi / 2 ;
 y = int ((sqrt (1 - ( x - x2 )^2)) , x0 , x1);
 z = int (cos(x), x1 , x2 );
 A = z + y ;

Answer 1

[Walter Roberson]

You can use the symbolic toolbox to attempt a closed-form integration if you command

syms x

However, you are probably expected to use numeric integration, which uses integral() of a function handle, not int() with a formula.

Also, for numeric work you need to use .^ instead of ^

   y = integral( @(x) (sqrt (1 - ( x - x2 ).^2)) , x0 , x1);