Can These Two Complex Math Equations Be Solved Correctly?

  • Thread starter Thread starter RaYaMe
  • Start date Start date
AI Thread Summary
The discussion revolves around solving two complex math equations in preparation for an upcoming exam. The first equation involves finding constants a and b in the relationship q=ap^b using given logarithmic values. The user attempts to derive values for a and b by taking the natural logarithm of both sides and manipulating the equations, ultimately calculating b as -0.25 and a as e^2.06. The second equation requires combining logarithms, which the user approaches by expressing logb(x) + n as a single logarithm. The responses confirm the user's methods and calculations as correct.
RaYaMe
Messages
3
Reaction score
0


Hi every body , I had a lot of equations to solve yesterday

becouse that i was preparing my self for my exam this sunday

and I've did .. but these TWO equations .. i couldn't be sure about my results

can you help me to solve them ..

1- The variables p and q are related by the law q=ap^b , where a and b are constants . Given that ln(p) = 1.32 when ln(q)= 1.73 and ln(p)=0.44 when ln(q)=1.95 ,
find the values of a and b .

2- Write logb (x) + n as one logarithm


* b is the base

 
Last edited:
Mathematics news on Phys.org
Welcome to PF!

Hi RaYaMe! Welcome to PF! :smile:

(try using the X2 tag just above the Reply box :wink:)

Show us what you got, and then we'll know how to help! :smile:
 
for the second one ..
2- Write logb (x) + n as one logarithm

i've tried =>

logb (x) + logb (b)^n = logb (X.b^n) ?? or it's canceled

:biggrin:

AND ..the first one .. i tried to take ln of both sides ( q=ap^b)

lnq = lna + b lnp

It'll be >> 1- 1.73= lna + 1.32 b

>> 2- 1.95 = lna + 0.44 b

that's what I've did to get the value of " b "

1.73=lna + 1.32 b
-1.95 = -lna - 0.44 b
___________________
-0.22 = 0.88 b >>>>> b= -0.22/0.88 = -0.25

1.73 = lna + ( 1.32 * -0.25 )
1.73 + 0.33 = lna
2.06 = lna

so , a = e^2.06 :biggrin: what do you think about my ways ..
 
Last edited:
RaYaMe said:
logb (x) + logb (b)^n = logb (X.b^n)

-0.22 = 0.88 b >>>>> b= -0.22/0.88 = -0.25

1.73 = lna + ( 1.32 * -0.25 )
1.73 + 0.33 = lna
2.06 = lna

so , a = e^2.06 :biggrin: what do you think about my ways ..

Yes, that looks fine! :smile:
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Thread 'Video on imaginary numbers and some queries'
Hi, I was watching the following video. I found some points confusing. Could you please help me to understand the gaps? Thanks, in advance! Question 1: Around 4:22, the video says the following. So for those mathematicians, negative numbers didn't exist. You could subtract, that is find the difference between two positive quantities, but you couldn't have a negative answer or negative coefficients. Mathematicians were so averse to negative numbers that there was no single quadratic...
Thread 'Unit Circle Double Angle Derivations'
Here I made a terrible mistake of assuming this to be an equilateral triangle and set 2sinx=1 => x=pi/6. Although this did derive the double angle formulas it also led into a terrible mess trying to find all the combinations of sides. I must have been tired and just assumed 6x=180 and 2sinx=1. By that time, I was so mindset that I nearly scolded a person for even saying 90-x. I wonder if this is a case of biased observation that seeks to dis credit me like Jesus of Nazareth since in reality...
Back
Top