Quick Algebra Ques

[rdf8585]

I need to find the value of the exponential function y=2.50(3.50)^1.4x when x is = 2

Does that mean y=2.50(3.50)^1.42

or

y=2.50(3.50)^1.4(2)

???

 

[EricNau]

It would be, 1.4(2)

 

[pknz]

<_<

>_>

I did not read this then run away. Ummm my battery died?

Edit: Actually thats not hard at all, I believe EricNau is correct

 

[Doctor Q]

Google doesn't interpret it right unless you parenthesize properly:

Search: 2.50(3.50)^1.4(2)
Result: 2.50 * (3.50^1.4) * 2 = 28.8845274

Search: 2.50(3.50)^(1.4(2))
Result: 2.50 * (3.50^(1.4 * 2)) = 83.4315924

 

[savar]

Google doesn't interpret it right unless you parenthesize properly:

Huh?

2.50(3.50)^1.4(2)

Order of operations is ^ before *

I think Google knows algebra 😀

 

[rdf8585]

3. Solve this exponential equation for x: e^5x= 1 over e^2x+7

4. Solve this exponential equation for x: 2^4x-7=32

are these answers right?

3...... -1
4....... no idea........

 

[Doctor Q]

Huh?

2.50(3.50)^1.4(2)

Order of operations is ^ before *

I think Google knows algebra 😀

I disagree. Look at the original problem: y=2.50(3.50)^1.4x. I don't think that's intended to be 2.50 * (3.50 ^ 1.4) * x. I think the product 1.4x is to be treated as the exponent, i.e., 2.50 * ( 3.50 ^ ( 1.4 * x ) ). But if you change x to a constant value, 2.50(3.50)^1.4(2), Google doesn't handle it way rdf8585's problem requires.

In other words, I would interpret 2 ^ 3 * 4 as (2^3)*4, as Google does, but I would interpret 2 ^ 3x as 2 ^ (3 * x) because with the juxtaposition implying implicit multiplication. So my point is that you have to add more parens to get the right answer from Google.

 

[Bobdude161]

I wouldn't be using Google all that much to calculate my Algebra problems. I used to have Maple and that piece of software had so many options to solving any equation you could think of. I would know, I had to take a class that taught how to use the software, barely passed it. 😱

 

[pknz]

Asking a mathematical question on MR is guaranteed to start a quarrel.

Its odd that Maths is so 'opinionated.'

 

[Doctor Q]

It's my fault we're talking about math. I meant the discussion to be about teaching errors, but since my examples were about math, and I can't resist talking about math, I'll have to take the blame. 🙁 🙂

 

[Atlasland]

3. Solve this exponential equation for x: e^5x= 1 over e^2x+7

4. Solve this exponential equation for x: 2^4x-7=32

are these answers right?

3...... -1
4....... no idea........

3) x = -1

4) x = 3