Thursday 2 August 2018

LOGARITHMS 1


Simplify Log21024 - Log327

Solution

= Log21024 - Log327

= Log2210 - Log333

= 10Log22 - 3Log33

= (10 x 1) - (3 x 1)

= 10 - 3

= 7

Hence Log21024 - Log327 = 7

TRY THIS..................



Simplify Log2256 – Log5125

EXPONENTIALS 1


If 52w (40w) = 0.000001 ; Find w.

Solution

52w (40w) = 0.000001

(52)w (40w) = 10-6

(25)w (40w) = 10-6

(25 x 40)w = 10-6

(1000)w = 10-6

(103)w = 10-6

103w = 10-6   (Bases are alike, so they cancel out)

3w = -6

3w = -62
3       3

w = -2

TRY THIS…………………………   


If 42a (2a) = 128 ; Find a.

FUNCTIONS 1


If f(x) = x4 + kx2 + 6x + 7 has a remainder of 10 when divided by x+2; find k.

Solution

f(x) = x4 + kx2 + 6x + 7

x + 2 = 0

x = -2

f(x) = (-2)4 + k(-2)2 + 6(-2) + 7 = 10

16 + 4k + (-12) + 7 = 10

16 + 4k - 12 + 7 = 10

16 + 4k - 5 = 10

4k + 16 - 5 = 10

4k + 11= 10

4k = 10 - 11

4k = -1

4k = -1
4      4

k = -1/4

hence k= -1/4

TRY THIS......................
  

If f(x) = x4 - kx2 + 2x - 1 has a remainder of 18 when divided by x-3; find k.

VARIATION 1


x is directly proportional to y. x=32 while y=4. Find y when x is 184.

Solution

x y
x = ky

32 = k x 4

32 = 4k    [dividing by 4 both sides]
4      4

k = 8
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

k = 8, y= ? x = 184.

x = ky

184 = 8 x y

184 = 8y
8        8

y = 23.

TRY THIS…………….


x is directly proportional to y. x=40 while y=4. Find y when x is 170.

SLOPE/GRADIENT 1


Find the slope of a line which passes through (-11, -8) and (6,-9)

Solution

x1 = -11,  y1 =-8,  x2 = 6,  y2 = -9

m = y2 –y1
       x2 – x1

m =   -9 –(-8)
          6 –(-11)

m =   -9 + 8
          6 + 11

m =    - 1
            17

Hence the slope is -1/17


TRY THIS……………………… 


Find the slope of a line which passes through (-11, -2) and (9,-14)

POLYGONS 1


A regular polygon has 64 sides. Find the total degrees of that polygon.

Solution

n = 64

Total degrees = (n - 2)1800

                       = (64 – 2)1800

                       = 62 x 1800

                       = 111600

Total degrees = 111600


TRY THIS……………………….


A regular polygon has 76 sides. Find the total angles of that polygon.