JEE MAIN - Mathematics (2020 - 4th September Morning Slot)
1
A survey shows that 63% of the people in a city read newspaper A whereas 76% read
newspaper B. If x% of the people read both the newspapers, then a possible value of x can be:
Answer
(D)
55
2
The probability of a man hitting a target is $${1 \over {10}}$$. The least number of shots required, so that the
probability of his hitting the target at least once is greater than $${1 \over {4}}$$, is ____________.
Then $${{{a_7}} \over {{a_{13}}}}$$ is equal to ______.
Answer
8
4
If the system of equations
x - 2y + 3z = 9
2x + y + z = b
x - 7y + az = 24, has infinitely many solutions, then a - b is equal to.........
Answer
5
5
Suppose a differentiable function f(x) satisfies the identity f(x+y) = f(x) + f(y) + xy2 + x2y, for all real x and y.
$$\mathop {\lim }\limits_{x \to 0} {{f\left( x \right)} \over x} = 1$$, then f'(3) is equal to ______.
where a > b > 0, then $${{dx} \over {dy}}\,\,at\left( {{\pi \over 4},{\pi \over 4}} \right)$$ is :
Answer
(C)
$${{a + b} \over {a - b}}$$
7
Two vertical poles AB = 15 m and CD = 10 m are standing apart on a horizontal ground with points A
and C on the ground. If P is the point of intersection of BC and AD, then the height of P (in m)
above the line AC is :
Answer
(D)
6
8
The mean and variance of 8 observations are 10 and 13.5, respectively. If 6 of these observations
are 5, 7, 10, 12, 14, 15, then the absolute difference of the remaining two observations is :
and $${A^5} = \left[ {\matrix{
a & b \cr
c & d \cr
} } \right]$$, where $$i = \sqrt { - 1} $$ then which one of the following is
not true?
Answer
(D)
$${a^2} - {b^2} = {1 \over 2}$$
10
Let $$u = {{2z + i} \over {z - ki}}$$, z = x + iy and k > 0. If the curve represented by Re(u) + Im(u) = 1 intersects the y-axis at the points P and Q where PQ = 5, then the value of k is :
Answer
(A)
2
11
Let $$\alpha $$ and $$\beta $$ be the roots of x2 - 3x + p=0 and $$\gamma $$ and $$\delta $$ be the roots of x2 - 6x + q = 0. If $$\alpha, \beta, \gamma, \delta $$
form a geometric progression.Then ratio (2q + p) : (2q - p) is:
Answer
(A)
9 : 7
12
Let f be a twice differentiable function on (1, 6). If f(2) = 8, fâ(2) = 5, fâ(x) $$ \ge $$ 1 and f''(x) $$ \ge $$ 4, for all x $$ \in $$ (1, 6), then :
Answer
(B)
f(5) + f'(5) $$ \ge $$ 28
13
Let $$f\left( x \right) = \int {{{\sqrt x } \over {{{\left( {1 + x} \right)}^2}}}dx\left( {x \ge 0} \right)} $$. Then f(3) â f(1) is eqaul to :
Let $$f(x) = \left| {x - 2} \right|$$ and g(x) = f(f(x)), $$x \in \left[ {0,4} \right]$$. Then $$\int\limits_0^3 {\left( {g(x) - f(x)} \right)} dx$$ is equal to:
Answer
(A)
1
15
The integral $$\int {{{\left( {{x \over {x\sin x + \cos x}}} \right)}^2}dx} $$ is equal to
(where C is a constant of integration):
Answer
(C)
$$\tan x - {{x\sec x} \over {x\sin x + \cos x}} + C$$
16
Let $${{{x^2}} \over {{a^2}}} + {{{y^2}} \over {{b^2}}} = 1$$ (a > b) be a given ellipse, length of whose latus rectum is 10. If its eccentricity is the maximum value of the function, $$\phi \left( t \right) = {5 \over {12}} + t - {t^2}$$, then a2 + b2 is equal to :
Answer
(B)
126
17
Let y = y(x) be the solution of the differential equation, xy'- y = x2(xcosx + sinx), x > 0. if y ($$\pi $$) = $$\pi $$ then $$y''\left( {{\pi \over 2}} \right) + y\left( {{\pi \over 2}} \right)$$ is equal to :
Answer
(C)
$$2 + {\pi \over 2}$$
18
Let [t] denote the greatest integer $$ \le $$ t. Then the equation in x,
[x]2 + 2[x+2] - 7 = 0 has :