help (1 Viewer)

[Arithela]

simplify: 4.8 x 10⁵(1.12ⁿ - 1)/0.12

just multiply 4.8 x 10^5 by 0.12? but i get an incorrect answer (to the successone book answer)

 

[tommykins]

Divide 4.8*10^5 by 0.12 as the fraction shows. You get 4,000,000.

4,000,000(1.12ⁿ - 1) = 4480000ⁿ - 4000000 ?

I'm not sure how simplified the answer is asking for.

 

[Arithela]

thanks - dividing it by 0.12 was the key but why divide and not multiply? sorry!

 

[tommykins]

If you write it on paper -
4.8 x 10⁵(1.12ⁿ - 1)/0.12 is

4.8 x 10⁵(1.12ⁿ - 1)
-----------------------------------------
0.12

Which is basically -
(4.8 x 10⁵)*(1.12ⁿ - 1)
-----------------------------------------
0.12

Since the 1.12ⁿ causes abit of trouble, we have a definite value for (4.8 x 10⁵), hence dividing it by 0.12 will give a simpler answer.

You can't multiply it by 0.12 because that completely changes the equation. You can however, multiply it by 0.12/0.12 (as this = 1) but that'd still yield you the original expression.

 

[Arithela]

yup- got it. thanks!

 

[Arithela]

another question

differentiate A = 1/2*[squareroot(m² + 4b)]*(mx - x² + b)

 

[tommykins]

Is that
(mx-x²+b)
----------
2sqrt(m²+4b) ?

I'm going to assume we're differentiating with respect to x.

 

[Arithela]

sqrt(m²+4b) is on top, multiplied by (mx-x²+b), all over 2

yes its dA/dx

 

[tommykins]

The sqrt(m²+4b) becomes 0 as they are constants.

 

[Arithela]

thank u so much

sqrt(m²+4b) = 0 is where they got me