simple math help

[noob with an RS 10+ year member]

ok im in college and im keeping up with my math and algebra so far but im slipping when it comes to remembering the basic rules.. please explain how to solve this simple math problem.. i had to come up with the answer by plugging numbers in and it took forever when i know it should be easy for me.. so if anyone could walk me through this simple problem id appreciate it..

a right triangle who's hypotenuse is 26 inches has two legs.. one leg is 14 inches longer than the other.. so basically im assuming the equation should look like this:

 

(L)^2 + (L+14)^2 = (26)^2 {since A squared plus B squared equals C squared}

now how do i do the math?!?

PS - ^2 means squared and when solved correctly, L equals 10.. i just dont understand how to get to that answer by hand!

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[Range Rover 10+ year member]

http://mathworld.wolfram.com/RightTriangle.html

Maybe here

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[j3bus2k3 5,000+ posts]

factor it out to be L^2+L^2+28L+196=676...and then solve from there. If it doesnt come out to a factorable form, use the quadratic equation.

 

[noob with an RS 10+ year member]

factor it out to be L^2+L^2+28L+196=676...and then solve from there. If it doesnt come out to a factorable form, use the quadratic equation.

yea thats the farthest i got though... starting from where you left off i would subtract 196 from both sides right? and that leaves me with:

L^2+L^2+28L=480

but now what can i do to get L alone? i think about dividing 28 to get that L alone but that gives me a long irrational number.. and i cant get rid of the exponents can i? and if i wanted to use the quadratic formula wouldnt the proper way to write it be: 2L^2+28L-480=0 (where A=2, B=28, and C=-480?) if this quadratic formula is correct, man, thats too huge for me to even calculate... help me!!

 

[j3bus2k3 5,000+ posts]

2L^2+28L-480=0..then factor (if possible) or use the quadratic equation "the opposite of b plus-or-minue the square-root of 4*A*C all over 2*A". I have no idea how else to put it other than on paint.

Better yet, Get a graphinc calculator and find where the graph crosses the x-axis, where it crosses will be your answers.

 

[noob with an RS 10+ year member]

ok i just realized that 2L^2+28L+196 is a perfect square so i think this problem was designed to be factored and set equal to 676 to be solved. but MAN, that is a lot of brain work to factor.... and is just one of many problems in my homework... //content.invisioncic.com/y282845/emoticons/furious.gif.fc81ca146dbff91fede3ed290dbc4f4c.gif

wait a minute.. if 2L^2+28L+196 equals 676, can i still solve the problem factoring or does it HAVE TO equal zero??

 

[j3bus2k3 5,000+ posts]

heh...nice. If you get into upper calc your going to be rippen your hair out. Or doing what I did....dropping the class, lol.

 

[noob with an RS 10+ year member]

i just skipped this **** prooblem.... i just dont think im capable of processing all that fuccing math.. anyone wanna help me with this next stupid word problem that's getting on my nerves?

THE HEIGHT OF A FLARE (IN FEET) ABOVE THE WATER, t SECONDS AFTER BEING FIRED, IS GIVEN BY THE FORUMLA h = -16t^2 + 112t +15. IF THE FLARE IS DESIGNED TO EXPLODE WHEN IT REACHES ITS HIGHEST POINT, AT WHAT POINT WILL THIS HEIGHT OCCUR?

how the hell am i suppose to know when the **** flare will explode.. what concept am i missing here..?

 

[helotaxi 5,000+ posts]

Set the first derivative equal to zero. That is the apogee point. Solve for "t". Then plug your answer into the original equation and get "h".

 

[Heresy 10+ year member]

i just skipped this **** prooblem.... i just dont think im capable of processing all that fuccing math.. anyone wanna help me with this next stupid word problem that's getting on my nerves?
THE HEIGHT OF A FLARE (IN FEET) ABOVE THE WATER, t SECONDS AFTER BEING FIRED, IS GIVEN BY THE FORUMLA h = -16t^2 + 112t +15. IF THE FLARE IS DESIGNED TO EXPLODE WHEN IT REACHES ITS HIGHEST POINT, AT WHAT POINT WILL THIS HEIGHT OCCUR?

how the hell am i suppose to know when the **** flare will explode.. what concept am i missing here..?

It is Newtonian physics, the flare will reach its point when the velocity of the flare is canceled out by the force of gravity (assuming no friction). That is the concept. However, I forgot how to do the problem without using calculus. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[RandyJ 10+ year member]

However, I forgot how to do the problem without using calculus. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

I had MATH102 (alg) just last semester and I have already forgotten it:naughty:

I do however, know how to find the exac value of sin135 by way of sin(90+45)//content.invisioncic.com/y282845/emoticons/up2something.gif.dd110ecf3ae4b76050d87598f2f8de7c.gif

 

[j3bus2k3 5,000+ posts]

Do you just want the answer? I can do it in less than a minute and PM, or AIM it to you....

 

[RandyJ 10+ year member]

h = -16t^2 + 112t +15.

It seems to me that there is some piece of information missing. IS the velocity of the projectile given? Without that, we can assume it was fired at 2.998x10^38 m/s, or fired at 10 m/s. Get what I'm saying?

 

[RandyJ 10+ year member]

Do you just want the answer? I can do it in less than a minute and PM, or AIM it to you....

How can you do it without knowing the velocity of the projectile?

 

[j3bus2k3 5,000+ posts]

You dont need the velocity to find the maximum atainable height. Like a poster said before, you take the first derivative and set it equal to zero. That equation will give you the velocity at any point on the graph, by setting it equal to zero, your finding the point where the velocity is zero and perhaps the maximum height. I can tell you right now just by looking at the equation that it was fired 15 "units" above the surface.