please write every answer with question number

Question 18 Determine if the following statement is an identity. tanh (x) + sech (x) = 1 O The statement is not an identity O The statement is an identity Submit QuestionQuestion 19 Evaluate the given function. Round any decimal answers to 3 decimal places, keep fractions exact (this happens with any problems with In). sinh( - 1) = cosh (In(20)) = tanh( - 9) = Submit QuestionQuestion 20 If cosh(0) = 19 7 and 0