Entered Answer Preview Result cos(3*t-(pi/4)) -[sqrt(2)]*cos((-pi/4)-3*t) cos(31) incorrect - (√2) cos(-31) incorrect At least one of the answers above is NOT correct. 1 of the questions remains unanswered. (1 point) (a) Using a trig identity, write x(t) = cos(3t) - sin(3t) using only one cosine function. x(t)=((cos(3t-pi/4))) help (formulas) (b) Using a trig identity, write x(t) = - (cos(3t)) - sin(3t) using only one cosine function. x(t)=-sqrt2(cos(-pi/4-3t)) help (formulas) (c) Using a trig identity, write x(t) = e−3 (cos(3t) - sin(3t)) using only one cosine function in your answer. x(t) = Hint: help (formulas) incorrect