IIT-JEE 1982

If \(a{x^2} + {b \over x} \ge c\) for all positive \(x\) where \(a>0\) and \(b>0\) show that \(27a{b^2} \ge 4{c^3}\).

If \(f(x)\) and \(g(x)\) are differentiable function for \(0 \le x \le 1\) such that \(f(0)=2\), \(g(0)=0\), \(f(1)=6\); \(g(1)=2\), then show that there exist \(c\) satisfying \(0 < c < 1\) and \(f'(c)=2g'(c)\).

The area bounded by the curves \(y=f(x)\), the \(x\)-axis and the ordinates \(x=1\) and \(x=b\) is \((b-1)\) sin \((3b+4)\). Then \(f(x)\) is

For any real \(t,\,x = {{{e^t} + {e^{ - t}}} \over 2},\,\,y = {{{e^t} - {e^{ - t}}} \over 2}\) is a point on the
hyperbola \({x^2} - {y^2} = 1\). Show that the area bounded by this hyperbola and the lines joining its centre to the points c...

If A and B are points in the plane such that PA/PB = k (constant) for all P on a given circle, then the value of k cannot be equal to ..........................................

If \(z = {\left( {{{\sqrt 3 } \over 2} + {i \over 2}} \right)^5} + {\left( {{{\sqrt 3 } \over 2} - {i \over 2}} \right)^5},\) then

The inequality |z-4| < |z-2| represents the region given by

Show that \(\int\limits_0^\pi {xf\left( {\sin x} \right)dx} = {\pi \over 2}\int\limits_0^\pi {f\left( {\sin x} \right)dx.}\)

Find the value of \(\int\limits_{ - 1}^{3/2} {\left| {x\sin \,\pi \,x} \right|\,dx}\)

If \(y = f\left( {{{2x - 1} \over {{x^2} + 1}}} \right)\) and \(f'\left( x \right) = \sin {x^2}\), then \({{dy} \over {dx}} = ..........\)

Let \(f\) be a twice differentiable function such that
\(f''\left( x \right) = - f\left( x \right),\) and $$f'\left( x \right) = g\left( x \right),h\left( x \right) = {\left[ {f\left( x \right)} \right]^2} + {\left[ {g\left( x \right)} \r...

The sum of the coefficients of the plynomial \({\left( {1 + x - 3{x^2}} \right)^{2163}}\) is ...............

The larger of \({99^{50}} + {100^{50}}\) and \({101^{50}}\) is ..............

Prove that \({7^{2n}} + \left( {{2^{3n - 3}}} \right)\left( {3n - 1} \right)\) is divisible by 25 for any natural number \(n\).

\(A\) is point on the parabola \({y^2} = 4ax\). The normal at \(A\) cuts the parabola again at point \(B\). If \(AB\) subtends a right angle at the vertex of the parabola. Find the slope of \(AB\).

Ten different letters of an alphabet are given. Words with five letters are formed from these given letters. Then the numbers of words which have at least one letter repeated are

In a certain test, \({a_i}\) students gave wrong answers to atleast i questions, where i = 1, 2,..., k. No student gave more than k wrong answers. The total number of wrong answers given is.....................................

The value of the expression \(\,{}^{47}{C_4} + \sum\limits_{j = 1}^5 {^{52 - j}\,{C_3}}\) is equal to

Eight chairs are numbered 1 to 8. Two women and three men wish to occupy one chair each. First the women choose the chairs from amongst the chairs marked 1 to 4; and then the men select the chairs from amongst the remaining. The number of p...

\(A\) and \(B\) are two candidates seeking admission in \(IIT.\) The probability that \(A\) is selected is \(0.5\) and the probability that both \(A\) and \(B\) are selected is atmost \(0.3\). Is it possible that the probability of \(B\) g...

If \(A\) and \(B\) are two events such that \(P\left( A \right) > 0,\) and \(P\left( B \right) \ne 1,\) then \(P\left( {{{\overline A } \over {\overline B }}} \right)\) is equal to

A vertical pole stands at a point \(Q\) on a horizontal ground. \(A\) and \(B\) are points on the ground, \(d\) meters apart. The pole subtends angles \(\alpha\) and \(\beta\) at \(A\) and \(B\) respectively. \(AB\) subtends an angle $$\g...

The number of real solutions of the equation \({\left| x \right|^2} - 3\left| x \right| + 2 = 0\) is

\(mn\) squares of equal size are arranged to from a rectangle of dimension \(m\) by \(n\), where \(m\) and \(n\) are natural numbers. Two squares will be called ' neighbours ' if they have exactly one common side. A natural number is writte...

Show that the equation \({e^{\sin x}} - {e^{ - \sin x}} - 4 = 0\) has no real solution.

Two towns A and B are 60 km apart. A school is to be built to serve 150 students in town A and 50 students in town B. If the total distance to be travelled by all 200 students is to be as small as possible, then the school should be built a...

The largest interval for which \({x^{12}} - {x^9} + {x^4} - x + 1 > 0\) is

The coeffcient of \({x^{99}}\) in the polynomial (x -1) (x - 2)...(x - 100) is ..............

If \(2 + i\sqrt 3\) is root of the equation \({x^2} + px + q = 0\), where p and q are real, then (p, q) = (..........,....................).

If p, q, r are any real numbers, then

If \(x,\,y\) and \(z\) are \(pth\), \(qth\) and \(rth\) terms respectively of an A.P. and also of a G.P., then \({x^{y - z}}\,{y^{z - x}}\,{z^{x - y}}\) is equal to :

The third term of a geometric progression is 4. The product of the first five terms is

Does there exist a geometric progression containing \(27, 8\) and \(12\) as three of its terms? If it exits, how many such progressions are possible ?

The set of lines \(ax + by + c = 0,\) where \(3a + 2b + 4c = 0\) is concurrent at the point ..........

\(y = {10^x}\) is the reflection of \({\log _{10}}\,x\) in the line whose equation is ...........

Without using tables, prove that \(\left( {\sin \,{{12}^ \circ }} \right)\left( {\sin \,{{48}^ \circ }} \right)\left( {\sin \,{{54}^ \circ }} \right) = {1 \over 8}.\)

Find all values of \(\lambda\) such that \(x, y, z,\)\(\, \ne\)\((0,0,0)\) and
$$\left( {\overrightarrow i + \overrightarrow j + 3\overrightarrow k } \right)x + \left( {3\overrightarrow i - 3\overrightarrow j + \overrightarrow k } \r...

For non-zero vectors \({\overrightarrow a ,\,\overrightarrow b ,\overrightarrow c },\) $$\left| {\left( {\overrightarrow a \times \overrightarrow b } \right).\overrightarrow c } \right| = \left| {\overrightarrow a } \right|\left| {\overrig...

\({A_1},{A_2},.................{A_n}\) are the vertices of a regular plane polygon with \(n\) sides and \(O\) is its centre. Show that
$$\sum\limits_{i = 1}^{n - 1} {\left( {\overrightarrow {O{A_i}} \times {{\overrightarrow {OA} }_{i + 1}...