JAMB Mathematics Past Questions & Answers - Page 335

1,671.

If y = 4x3 - 2x2 + x, find \(\frac{\delta y}{\delta x}\)

A.

8x2 - 2x + 1

B.

8x2 - 4x + 1

C.

12x2 - 2x + 1

D.

12x2 - 4x + 1

Correct answer is D

If y = 4x3 - 2x2 + x, then;

\(\frac{\delta y}{\delta x}\) = 3(4x2) - 2(2x) + 1

= 12x2 - 4x + 1

1,672.

If \(\sin\theta = \frac{12}{13}\), find the value of \(1 + \cos\theta\)

A.

\(\frac{25}{13}\)

B.

\(\frac{18}{13}\)

C.

\(\frac{8}{13}\)

D.

\(\frac{5}{13}\)

Correct answer is B

No explanation has been provided for this answer.

1,673.

Calculate the mid point of the line segment y - 4x + 3 = 0, which lies between the x-axis and y-axis.

A.

\(\begin{pmatrix} 3 & -3 \\ 8 & 2 \end{pmatrix}\)

B.

\(\begin{pmatrix} 3 & 3 \\ 8 & 2 \end{pmatrix}\)

C.

\(\begin{pmatrix} -2 & 2 \\ 2 & 2 \end{pmatrix}\)

D.

\(\begin{pmatrix} -2 & 3 \\ 3 & 2 \end{pmatrix}\)

Correct answer is A

y - 4x + 3 = 0

When y = 0, 0 - 4x + 3 = 0

Then -4x = -3

x = 3/4

So the line cuts the x-axis at point (3/4, 0).

When x = 0, y - 4(0) + 3 = 0

Then y + 3 = 0

y = -3

So the line cuts the y-axis at the point (0, -3)

Hence the midpoint of the line y - 4x + 3 = 0, which lies between the x-axis and the y-axis is;

\([\frac{1}{2}(x_1 + x_2), \frac{1}{2}(y_1 + y_2)]\)

\([\frac{1}{2}(\frac{3}{4} + 0), \frac{1}{2}(0 + -3)]\)

\([\frac{1}{2}(\frac{3}{4}), \frac{1}{2}(-3)]\)

\([\frac{3}{8}, \frac{-3}{2}]\)

1,674.

The gradient of a line joining (x,4) and (1,2) is \(\frac{1}{2}\). Find the value of x

A.

5

B.

3

C.

-3

D.

-5

Correct answer is A

\(\text{Gradient m} = \frac{y_2 - y_1}{x_2 - x_1}\)

\(\frac{1}{2} = \frac{2 - 4}{1 - x}\)

1 - x = 2(2 - 4)

1 - x = 4 - 8

1 - x = -4

-x = -4 - 1

x = 5

1,675.

Find the mid point of S(-5, 4) and T(-3, -2)

A.

-4, 2

B.

4, -2

C.

-4, 1

D.

4, -1

Correct answer is C

Mid point of S(-5, 4) and T(-3, -2) is

\([\frac{1}{2}(-5 + -3), \frac{1}{2}(4 + 2)]\)

\([\frac{1}{2}(x_1 + x_2), \frac{1}{2}(y_1 + y_2)]\)

\([\frac{1}{2}(-8), \frac{1}{2}(2)]\)

\([-4, 1]\)