Please answer all questions and show work:

17) Find the tangent vector, r' (2) to the O r(2) = -21 - In3j +ek space curve described by the given O r(2) = -37- 3jtek vector function. r'(t) = (-+ +t) i - In(t +1) jtek 1 j+ 2ek Or(2)= -j O r(2) =0 O None of the above 18) For an unknown vector a and the given vector b = (0, 0, 7) , it is also given that a x b = (0, - 21, c) , where c is unknown. Find the value of c. Enter only a number. Do NOT enter an equation. If the number is not an integer, enter it as a fraction in simplest form. If there is not enough information to determine the solution, "not enough information " should be entered. 19 Which of the equations could have the given graph? O x = y O x = / O y=-z O None of these