GradientTape:

Código desarrollado:

import tensorflow as tf

w = tf.Variable(3.0)
b = tf.Variable(1.0)
x = tf.constant(2.0)
yTrue = tf.constant(4.0)

with tf.GradientTape() as tape:
    x1 = x*w
    x2 = x1 + b
    lossVal = abs(yTrue-x2)

gradientes = tape.gradient(lossVal, [w, b])
print(gradientes[0].numpy())
print(gradientes[1].numpy())