Definite integral

1103124301

Level: 
C
The picture shows graphs of two quadratic functions \( f_1(x) \) and \( f_2(x) \). Find the unknown real positive constant \( a \) (as shown in the picture) such that the value of the definite integral \( \int\limits_{-1}^1 f_1(x)\,\mathrm{d}x \) is greater by \( 8 \) than the value of the definite integral \( \int\limits_{-1}^1 f_2(x)\,\mathrm{d}x \).
\( a = 3 \)
\( a = 1 \)
\( a = 4 \)
\( a = 6 \)

2010013803

Level: 
C
Any positive real number \(x\) can be written as \(x=c+d\), where \(c\) is an integer and \(d\in[ \left. 0,1\right)\). Then \(c\) is called the integer part of \(x\) and is denoted by \(\left[x\right]\). Evaluate the following definite integral. \[\int\limits_{\frac52}^{2.8}\left[x\right]\,\mathrm{d}x \]
\(0.6\)
\(0.9\)
\(2\)
This integral cannot be evaluated.

2010013804

Level: 
C
Any positive real number \(x\) can be written as \(x=c+d\), where \(c\) is an integer and \(d\in[ 0,1 )\). Then \(c\) is called the integer part of \(x\) and is denoted by \(\left[x\right]\). Evaluate the following definite integral. \[\int\limits_{3.1}^{\frac72}\left[x\right]\mathrm{d}x \]
\(1.2\)
\(1.6\)
\(3\)
This integral cannot be evaluated.