how to find a root of polynomial using matlab

C (y) = 1 + 3 tan( y/√2)

Answer 1

[KSSV]

sym c(y) 
c(y)= 1+3*tan(y/sqrt(2))==0 ;
r = solve(c,y) ; 
double(r)

[KSSV]

It is not a polynomial .. how you expect to write?

Answer 2

[Alan Stevens]

Or directly

y = sqrt(2)*atan(-1/3);

[mustafa jbara]

how find roots

[Alan Stevens]

That gives you a root! i.e. a value of y that makes the expression 1+3*tan(y/sqrt(2)) equal zero.