4.
seems to be a geometric sequence
common ratio is -4
first erm is -2
[tex] a_{n}=-2(-4)^{n-1} [/tex]
5. x=-1
remember x^-1=1/x
f(-1)=4(7^-1)=4(1/7)=4/7
f(2)=4(7^2)=4(49)=196
6. remember
(ab)/(cd)=(a/c)(b/d)
also
(x^m)/(x^n)=x^(m-n)
and
(x^m)(x^n)=x^(m+n)
so
[tex] \frac{4.5*10^{3}}{9*10^{7}} [/tex]=
([tex] \frac{4.5}{9} [/tex])([tex] \frac{10^{3}}{10^{7}} [/tex])=
(0.5)([tex] 10^{3-7} [/tex]=
(0.5)(10^-4)=
(5)(10^-1)(10^-4)=
(5)(10^(-1-4)
5*10^-5
4. [tex] a_{n}=-2(-4)^{n-1} [/tex]
5. f(-1)=4/7
f(2)196
6. 5 times 10^-5
