[R] Problem in fitting model equation in "nls" function

Dear R users, I am struggling to fit expo-linear equation to my data using "nls" function. I am always getting error message as i highlighted below in yellow color: ### Theexpo-linear equation which i am interested to fit my data:   response_variable =  (c/r)*log(1+exp(r*(Day-tt))), wher

[R] Problem in Fitting model equation in "nls" function

Dear R users,   I am struggling to fit expo-linear equation to my data using "nls" function. I am always getting error message as i highlighted below in yellow color:     ### Theexpo-linear equation which i am interested to fit my data:   response_variable =  (c/r)*log(1+exp(r*(Day-tt))), w