Consider the density function f(x)equalsleft brace start 2 by 2 matrix 1st row 1st column k startroot x endroot comma 2nd column 0 less than x less than 1 comma 2nd row 1st column 0 comma 2nd column elsewhere. endmatrix (a) evaluate k. (b) find f(x) and use it to evaluate p(0.5less thanxless than0.9). (a) kequals three halves (type an integer or a simplified fraction.) (b) complete the definition of f(x).