Hi to all here is the question and I'll be providing my own answer which I guess it's wrong could any one tell me where I did mistake please?
Q:
My own (wrong) answer.The new rubish removal trucks were too high and were touching power cables.
Cables are hanging between poles along the side of a street with the poles 40 meters apart. the hight of the wires above the ground is given by:
y= 2(e^x/20 + e^-x/20)
the trucks are 3.4 m high and can extend 1.3 more while removing bins.
Explain whether the cables are high enough for the rubbish trucks to operate without becoming entangled in overhead cables strung between the power poles.
Mention the minimum height the power poles must be and also any change made to the equation for the centenary to accommodate the height change.
I've added 3.4 to 1.3 to get the overall hight which is: 4.7 right?
and I've placed it instead of x on the equation!
y= 2(e^4.7/20 + e^-4.7/20)
which is 4.10 and it's wrong i guess! isn't?
Thanks
Hi, thanks.
So we put the 4.7 instead of Y not x? may I ask why?
I'll see how it goes...
check me please.
we multiply 2e^x/20 x 2e^-x/20 right?
and we get 4e ^-x^2/40 ?
so we have:
4.7=4e^-x^2/40
we take 4 to to other side
0.7=e^-x^2/40
ln(0.7)=-x^2/40
and we take 40 other side:
40*ln(0.7)= -x^2
-14.26=-x^2
we have 3.77 which is wrong i guess where again i did mistake?