If you want to use the TensorFlow with the GPU, then you will need to install the CUDA and cuDNN. Please follow the instructions given on https://www.tensorflow.org/install/
If you are already done with the installation of CUDA and cuDNN, but still if you are facing this error, then you must have forgotten to export your libraries: So for the Linux, you may need to set the LD_LIBRARY_PATH to include CUDA libraries.
After installing the TensorFlow 1.11 GPU via the Anaconda with th below command
"conda install tensorflow-gpu" I also had experienced the same problem which you had. So before TF 1.11 I used the TF 1.04. Just before updating the TF I also updated the Nvidia Driver to the version 396 through the ppa.
There was no trace for the libcuda.so.1 in the entire linux.
After many trial and errors, my problem was resolved when I tried to change the nvidia driver to 390. The 390 version inserted the libcuda.so.1 to /usr/lib/i386-linux-gnu the directory, which completely solved the problem.