Mathematics Multiple Choice Questions on “Definite Integral”.
1. In (int_a^b)f(y) dy, what is ‘a’ called as?
a) Integration
b) Upper limit
c) Lower limit
d) Limit of an integral
Answer: b
Clarification: In (int_a^b)f(y) dy ‘a’ is the called as lower limit and ‘b’ is called the upper limit of the integral. The fuction f in (int_a^b)f(y) dy is called the integrand. The letter ‘y’ is a dummy symbol and can be replaced by any other symbol.
2. The value of (int_0^{pi })sin y dy is 2.
a) True
b) False
Answer: a
Clarification: (int_0^{pi })sin y dy = [-cos y]y0
= – cos π – (- cos 0)
= -(-1)-(-1)
= 2
3. Compute ∫cos(x)-(frac {3}{x4})dx.
a) sin(x)+(frac {3}{4})x-7+c
b) sec(x)+(frac {3}{4})x-3+c
c) sin(x)+(frac {3}{4})x-3
d) sin(x)+(frac {3}{4})x-3+c
Answer: d
Clarification: ∫cos(x)-(frac {3}{x4})dx = ∫cos(x) dx−∫3(x-4) dx
= sin(x)+(frac {3}{4})x-3+c
4. What is the value of (int_2^3)cos(x)-(frac {3}{x4})dx .
a) sin (3) – sin (2)
b) sin (3) – sin (9) – (frac {19}{288})
c) sin (8) – sin (2) – (frac {19}{288})
d) sin (3) – sin (2) – (frac {19}{288})
Answer: d
Clarification: (int_2^3)cos(x)-(frac {3}{x4})dx = (int_2^3)sin(x) dx + (int_2^3 frac {3}{4})x-3 dx
= (sin (3) + (frac {3}{4})3-3) – (sin (2) + (frac {3}{4})2-3)
= sin (3) – sin (2) – (frac {19}{288})
5. Evaluate (int_7^9)cos(x)dx.
a) 8 (-sin 9 – sin 7)
b) 8 (sin 9 + sin 7)
c) 8 (sin 9 – sin 7)
d) 7 (sin 9 – sin 7)
Answer: c
Clarification: (int_7^9)8cos(x)dx = 8 (int_7^9)cos(x)dx
= 8 (cos x)97
= 8 (sin 9 – sin 7)
6. Compute (int_2^3 frac {cosx-sinx}{4})dx.
a) (frac {1}{4}) (sin 2 + cos 3 – sin 3 – cos 2)
b) (frac {1}{4}) (sin 3 – cos 3 – sin 2 – cos 2)
c) (frac {1}{4}) (sin 3 + cos 3 – sin 2 – cos 2)
d) (frac {1}{4}) (sin 3 + cos 3 + sin 2 – cos 2)
Answer: c
Clarification: (int_2^3 frac {cosx-sinx}{4})dx = (frac {1}{4}) [sin x – (- cos x)]32
= (frac {1}{4}) (sin x + cos x)32
= (frac {1}{4}) (sin 3 + cos 3) – (frac {1}{4}) (sin 2 + cos 2)
= (frac {1}{4}) (sin 3 + cos 3 – sin 2 – cos 2)
7. What is y in (int_a^b)f(y) dy called as?
a) Random variable
b) Dummy symbol
c) Integral
d) Integrand
Answer: b
Clarification: In (int_a^b)f(y) dy ‘a’ is the called as lower limit and ‘b’ is called the upper limit of the integral. The fuction ‘f’ in (int_a^b)f(y) dy is called the integrand. The letter ‘y’ is a dummy symbol and can be replaced by any other symbol.
8. The value of (int_1^2)1y5 dy is_____
a) 10.5
b) 56
c) 9
d) 23
Answer: a
Clarification: (int_1^2)1y5 dy = (y6/6)21
= (frac {64}{6} – frac{1}{6})
= 10.5
9. The value of (int_1^2)1y5/5dy is _____
a) 12
b) 2.1
c) 21
d) 11.1
Answer: b
Clarification: (int_1^2)1y5/5dy = (frac {1}{5})(y6/6)21
= (frac {1}{5}(frac {64}{6} – frac{1}{6}))
= 2.1
10. Evaluate (int_0^{pi })sinx dx.
a) 2
b) 6
c) 17
d) 3
Answer: a
Clarification: (int_0^{pi })sinx dx = [- cos x]x0
= – cos π – (-cos 0)
= -(-1)-(-1)
= 2
11. Evaluate (int_2^3)cosx dx.
a) 38.2
b) sin (9) – sin (4)
c) 89.21
d) sin (3) – sin (2)
Answer: d
Clarification: (int_2^3)cosx dx = (sin x)32
= sin (3) – sin (2)
12. Compute (int_2^3)2ex dx.
a) 2(e9 – e4)
b) 84.32
c) 2(e3 – e2)
d) 83.25
Answer: c
Clarification: (int_2^3)2ex dx = 2(ex)32 dx
= 2(e3 – e2)
13. In (int_b^a)f(x) dx, b called as lower limit and a is called as upper limit.
a) False
b) True
Answer: b
Clarification: In (int_a^b)f(y) dy ‘a’ is the called as lower limit and ‘b’ is called the upper limit of the integral. The fuction ‘f’ in (int_a^b)f(y) dy is called the integrand. The letter ‘y’ is a dummy symbol and can be replaced by any other symbol.
14. Compute (int_3^6)9 ex dx.
a) 30.82
b) 9(e6 – e3)
c) 11.23
d) 81(e6 – e3)
Answer: b
Clarification: (int_3^6)9 ex dx = 9(ex)63 dx
= 9(e6 – e3)
15. Evaluate (int_3^7)sin(t)-2cos(t)dt.
a) cos(7) – 2sin(7) + (cos(3) + 2sin(3)
b) -17
c) 12
d) cos(7) – 2sin(7) – (cos(3) + 2sin(3)
Answer: d
Clarification: (int_3^7)sin(t)-2cos(t)dt = (cos(t)−2sin(t))73
= (cos(7) – 2sin(7)) – (cos(3) – 2sin(3))
= cos(7) – 2sin(7) – (cos(3) + 2sin(3)
