Which exponential functions represent exponential decay?

Select all that apply.

f(x)=0.25(1.5)3x

f(x)=(0.85)x

f(x)=(1.01)x

f(x)=1.8(0.6)x

f(x)=(0.95)2x-*

The function representing exponential decay are:

b)  

d)  

e)

Step-by-step explanation:

The exponential function is given as:

where , , and .

If and then the function represents exponential decay.

If   and then the function represents exponential growth.

Thus, we can check each function given.

a)

For the given function and . So, it represents exponential growth.

b)  

For the given function and . So, it represents exponential decay.

c)  

For the given function and . So, it represents exponential growth.

d)  

For the given function and . . So, it represents exponential decay.

e)

For the given function and . . So, it represents exponential decay.

∠ABC = 76°

BC = 20.1

CA = 28.0

Solving the triangle means finding all unknown angles and sides of the triangle.

(i) Two of the angles (∠BCA = 60° and ∠CAB  = 44°) are given. To find the third angle (∠ABC), use one of the theorems stating that the sum of angles of a triangle is equal to 180°.

Therefore, the sum of angles of the triangle ABC is 180°. i.e

∠ABC + ∠BCA + ∠CAB = 180°

=> ∠ABC + 60° + 44° = 180°

=> ∠ABC + 104° = 180°

=> ∠ABC = 180° - 104°

=> ∠ABC = 76°

(ii) One side (BA) of the triangle is given. To get the other sides, we use the sine rule as follows;

=>

=>

Substitute the necessary values

     ---------------------(ii)

(a) To get side BC, use the first two terms of equation (ii)

Cross multiply

BC x sin 60 = 25 x sin 44

BC x 0.8660 = 25 x 0.6947

0.8660 x BC = 17.3675

BC =

BC = 20.05

=> BC = 20.1 to the nearest tenth

(b) To get CA, use any two terms of equation (ii). Using the first and third terms, we have;

Cross multiply

CA x sin 60 = 25 x sin 76

CA x 0.8660 = 25 x 0.9703

0.8660 x CA = 24.2575

CA =

CA = 28.01

=> CA = 28.0 to the nearest tenth