Topic/Skill Definition/Tips
Topic: Growth and Decay Example
1. Exponential When we multiply a number repeatedly 1 ,2 , 4 , 8 ,16 , 32 , 64 , 128 … is an
Growth by the same number (≠ 1¿ , resulting in the example of exponential growth,
number increasing by the same because the numbers are being
proportion each time. multiplied by 2 each time.
The original amount can grow very quickly
in exponential growth.
2. Exponential When we multiply a number repeatedly 1000 , 200 , 40 , 8 … is an example of
Decay by the same number (0< x <1 ¿, resulting exponential decay, because the
in the number decreasing by the same 1
numbers are being multiplied by each
proportion each time. 5
time.
The original amount can decrease very
quickly in exponential decay.
3. Compound Interest paid on the original amount and A bank pays 5% compound interest a
Interest the accumulated interest. year. Bob invests £3000. How much
will he have after 7 years.
7
3000 ×1.05 =£ 4221.30
4. Exponential The equation is of the form y=a x, where a
Graph is a number called the base.
If a> 1 the graph increases.
If 0< a<1, the graph decreases.
The graph has an asymptote which is the
x-axis.
The y-intercept of the graph y=a x is (0,1)
s
Mr A. Coleman Glyn School
Topic: Growth and Decay Example
1. Exponential When we multiply a number repeatedly 1 ,2 , 4 , 8 ,16 , 32 , 64 , 128 … is an
Growth by the same number (≠ 1¿ , resulting in the example of exponential growth,
number increasing by the same because the numbers are being
proportion each time. multiplied by 2 each time.
The original amount can grow very quickly
in exponential growth.
2. Exponential When we multiply a number repeatedly 1000 , 200 , 40 , 8 … is an example of
Decay by the same number (0< x <1 ¿, resulting exponential decay, because the
in the number decreasing by the same 1
numbers are being multiplied by each
proportion each time. 5
time.
The original amount can decrease very
quickly in exponential decay.
3. Compound Interest paid on the original amount and A bank pays 5% compound interest a
Interest the accumulated interest. year. Bob invests £3000. How much
will he have after 7 years.
7
3000 ×1.05 =£ 4221.30
4. Exponential The equation is of the form y=a x, where a
Graph is a number called the base.
If a> 1 the graph increases.
If 0< a<1, the graph decreases.
The graph has an asymptote which is the
x-axis.
The y-intercept of the graph y=a x is (0,1)
s
Mr A. Coleman Glyn School
