Message Error “First input argument must be a function handle”

When trying to calculate the Integral of two variables, I faced the Error:

“First input argument must be a function handle”

Here is the code:

syms x;

a=0.4;

theta=(9 - 4*x*(5*x - 141/25))^(1/2)/2 - 3/2;

theta_prime=-(40*x - 564/25)/(4*(9 - 4*x*(5*x - 141/25))^(1/2));

g=(1/theta)*theta_prime

s=(1+a*(theta-1))*(g)^2

sgen = integral(s,x,0.1,1) %x=0.1:0.1: 1

What was my mistake? Please help.

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Walter Roberson]

integral() is for numeric integration. You need int() for symbolic integration