MATLAB: Error in fzero function

Question

why i got this error and how can i fix this?

Thank you..

a=log(0.5)*log10(30)*sin(pi/6); b=0.5*(atan(0.5))*3^(1/5);

fzero('x^3+2*a-b',-1)

FZERO cannot continue because user-supplied expression ==> x^3+2*a-b failed with the error below.

Error in inline expression ==> x^3+2*a-b Undefined function or variable 'a'.

Answer 1

Use a function handle. E.g.,

fzero(@(x)x^3+2*a-b,-1)