@problem@
	@problemtype@
		upload
	@;problemtype@
	@name@
		tutorial_20_upload_questions
	@endname@
	@answer@
		The solution, given by $x(t)=\cos(t)$, can be otained by finding the roots of the characteristic polynomial of the equation.
	@endanswer@
	@content@
		Some questions might be difficult or outright impossible to pose if only a simple answer field or a multiple choice selection is provided for the answer. In such cases, a more extensive solution (e.g. handwritten and scanned) can be uploaded and manually graded later.
		@pb;@
		For such questions, you can use the 'upload' problem type. Any upload problem needs to contain exactly one call to the 'upload' function, which specifies the achievable number of points as well as some additional options. In addition, a correct answer (or sample solution) can be provided which is shown in the exam feedback and displayed to the grader.
		@pb;@
		@hr;@
		@pb;@
		Find the solution $x\colon\mathbb{R}\to\mathbb{R}$ to the initial value problem
		\[
			x''' + x'' + x' + x = 0
			\,,\quad
			x(0)=1\,,\;
			x'(0)=0\,,\;
			x''(0)=-1\,.
		\]
		Show the details of your work!
		@pb;@
		@upload(10)@
	@;content@
@;problem@