# math question

• 05-01-2006
kryptkat
math question
Meow? Math question. Which is the correct way of doing this?

Say i have a math problem of AB2 <ab squared> converting it to c.

1 Do you multiply a times b then square
2 Do you square b then multiply by a

example a = 3 b =7

if you do it by number 1 you have 3*7 = 21 then square = 441

if you do it by number 2 you have 7 squared = 49 then times 3 = 147

which is the correct answer? Meow?

i have one book that says one way and another that says the other way?
• 05-01-2006
Perspective
BEDMAS

Brackets, exponents, division, multiplication, addition, subtraction

so, 2.
• 05-01-2006
xddxogm3
please someone correct me if i'm wrong, but i think you do it this way.

value of (a) multiplied by the value (b) squared
ab^2 = a * b^2 = 3 * 7^2 = 3 * 49 = 147
someVariable = a * sqrt(b);

otherwise you would need to do the following.
(ab)^2 = (a)^2 * (b)^2 = 3^2 * 7^2 = 9 * 49 = 441
notice how the brackets change everything
• 05-02-2006
kryptkat
good news.... eighter one give you an answer

bad news .... only a 50% chance of getting a correct answer

so if e = mv2 energy equals velosity squared
you square v then multiply by mass of 3grams? to get the energy correct answer. of 147 g/ftsec

ok thank you
• 05-02-2006
Sang-drax
If there are no parenthesis, like in e = mv^2, it means the same as e=m*(v^2), i.e. square v first, then multiply.
• 05-02-2006
anonytmouse
Assuming you are talking about kinetic energy, the equation is 1/2 mv^2, and you need to use consistent units, or the answer will be meaningless.
• 05-04-2006
kryptkat
thank you anonytmouse i forgot what the exact formula was and what units were used. i could not figure out if one of the books was wrong or if i had messed up. book wrong. besides the energy formula there are other things that use the d =ab^2 type math statement. so i thought i had better check to make sure i was doing things correctly. thank you all again.