JAMB Mathematics Past Questions & Answers - Page 309

1,541.

Calculate the distance between points L(-1, -6) and M(-3, -5)

A.

√5

B.

2√3

C.

√20

D.

√50

Correct answer is A

L\(\begin{pmatrix} x_1 & y_1 \\ -1 & -6 \end{pmatrix}\) m L\(\begin{pmatrix} x_2 & y_2 \\ -3 & -5 \end{pmatrix}\)

D = \(\sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}\)

D = \(\sqrt{(-3 - (-1)^2 + (-5 -(-6)^2}\)

D = \(\sqrt{(-3 + 1)^2 + (-5 + 6)^2}\)

D = \(\sqrt{(-2)^2 + 1^2}\)

D = \(\sqrt{4 + 1}\)

D = \(\sqrt{5}\)

1,542.

\(\begin{pmatrix} -2 & 1 \\ 2 & 3 \end{pmatrix}\) \(\begin{pmatrix}p & q \\ r & s\end{pmatrix}\) = \(\begin{pmatrix} 1 & 0 \\0 & 1 \end{pmatrix}\). What is the value of r?

A.

-\(\frac{1}{8}\)

B.

\(\frac{3}{8}\)

C.

\(\frac{5}{8}\)

D.

\(\frac{1}{4}\)

Correct answer is D

-2p + r = 1.......(i)

2p + 3r = 0.......(ii)

r - 1 + 2p ........(iii)

2p + 3(1 + 2p) = 0

2p + 3(1 + 2p) = 0

2p + 3 + 6p = 0

3 - 8p = 0 \(\to\) 8p = 3

p = \(\frac{3}{8}\)

6 = 1 - 2 \(\frac{3}{8}\)

= 1 - \(\frac{6}{8}\)

\(\frac{8 - 6}{8}\) = \(\frac{2}{8}\)

= \(\frac{1}{4}\)

1,543.

Find the values of x and y respectively if
\(\begin{pmatrix} 1 & 0 \\ -1 & -1\\ 2 & 2 \end{pmatrix}\) + \(\begin{pmatrix} x & 1 \\ -1 & 0\\ y & -2 \end{pmatrix}\) = \(\begin{pmatrix} -2 & 1 \\ -2 & -1\\ -3 & 0 \end{pmatrix}\)

A.

-3, -2

B.

-5, -3

C.

-2, -5

D.

-3, -5

Correct answer is D

\(\begin{pmatrix} 1 & 0 \\ -1 & -1\\ 2 & 2 \end{pmatrix}\) + \(\begin{pmatrix} x & 1 \\ -1 & 0\\ y & -2 \end{pmatrix}\) = \(\begin{pmatrix} -2 & 1 \\ -2 & -1\\ -3 & 0 \end{pmatrix}\)

therefore, (x, y) = (-3, -5) respectively

1,544.

What value of x will make the function x(4 - x) a maximum?

A.

4

B.

3

C.

2

D.

1

Correct answer is C

x(4 - x)

4x - x2

\(\frac{dy}{dx}\) = 4 - 2x

\(\frac{dy}{dx}\) = 0

2x = 4

x = \(\frac{4}{2}\)

= 2

1,545.

Determine the value of x for which (x2 - 1)>0

A.

x < -1 or x > 1

B.

-1 < x < 1

C.

x > 0

D.

x < -1

Correct answer is A

x(x - 1) > 0 x < -1 or x > 1