```
B1=24e3
B2=24e3
cvx_begin
variable a(2)
variable b(2)
R1= a(1)*B1 + 60000*b(1)*log2(1 +((7.48e3)*(0.7-a(1))*(133.736e-6)/(b(1))));
R2= a(2)*B2 + 60000*b(2)*log2(1 +((7.48e3)*(0.7-a(2))*(133.736e-6)/(b(2))));
maximize(R1 + R2)
subject to
sum(a)<= 0.7
sum(b) <= 0.3
a >= 0
b >= 0
cvx_end
```

(R1 + R2) are concav function but I get this error. What can I do. thank youâ€¦