A. Properties of Logarithm
1) a to the power of m times a to the power of n equals a to the power of m plus n in bracket.
2) a to the power of m over a to the power of n equals a to the power of m minus n in bracket.
3) Log b to the base of a equals n, means with b equals a to the power of n.
4) Log a to the base of g equal x, means with a equals g to the power of x.
5) Log b to the base of g equals y, means with b equals g to the power of y.
6) Log a times b in bracket to the base of g equals bla………bla……….bla……bla….
Example:
a. Log a to the base of g equals x, so a equals g to the power of x
b. Log b to the base of g equals y, so b equals g to the power of y.
a times b equals g to the power of x times g to the power of y.
a times b equals g to the power of x plus y in bracket.
Ø Log a times b in bracket to the base of g,
equals Log g to the power of x plus y in bracket to the base of g
equals x plus y in bracket times Log g to the base of g. Consider : Log g to the base g equals 1.
So, x plus y in bracket times Log g to the base of g equals 1.
So, Log a times b in bracket to the base of g equals Log a to the base of g plus Log b to the base of g.
Ø a over b equals g to the power of x over g to the power of y.
equivalen a over b equals g to the power of x minus in bracket.
equivalen Log a over b in bracket to the base of g equals Log g to the power of x minus y in bracket to the base of g.
equivalen Log a over b in bracket to the base of g equals x minus y in bracket times Log g to the base of g.
equivalen Log a over b in bracket to the base of g equals x minus y.
equivalen Log a over b in bracket to the base of g equals Log a to the base of g minus Log b to the base of g.
So, Log a over b in bracket to the base of g equals Log a to the base of g minus Log b to the base of g.
Ø Log a to the power of n to the base of g.
Log a to the power of n to the base of g equals Log a times a times a times a up to n factor,
Equivalen Log a to the power of n to the base of g equals Log a to the base of g plus Log a to the base of g plus Log a to the base of g plus bla…..bla…..bla….. plus Log a to the base of g plus Log a to the base of g.
Equivalen Log a to the power of n to the base of g equals n times Log a to the base of g
So, Log a to the power of n to the base of g equals n times Log a to the base of g.
B. Square Root of 2 is Irrational Number
Square root of 2 is the first irrational number is recognizedby Yunani people. They to say that long of diagonal from a right triangle with long of 2 side to form angled, one of them is irrational, from Phytagoras Theorem to get that long of triangle hypotenuse is a square root of 2.
So, How to prove that square root of 2 is irrational number?????????
Prove:
Square root of 2 is knowed by Yunani people that’s plane and that numeral is irrational. Supposing square root of 2 is rational, so must to be integer of x and y, so that square of 2 equals xper y, where y not zero. We can to confirm that x and y are not even (minimal one of them is a odd), because if both of them are even, we can to simplifying. In other meaning x per y we take the simplest. We get that x square per y square equals 2 or x square equals 2 times y square with other meaning x square is even. Because x square is even, so x is even, because that to be h even, so x equals 2 times h and thus
x square equals 2 times y square.
ð Open bracket 2 time h close bracket square equals 2 times y square.
ð 4 times h square equals 2 times y square,
ð y square equals 2 times h square.
Because y square is even, so that y is even too. This contradiction with we estimate that x and y cannot even, minimal one of them is odd, so that estimate is fllen and square root of 2 is irrational number.
(PROVED)
Prove with Math Logical, we use a implication.
If square root of 2 is irrational so that integer of x and y not zero, thus square root of 2 equal x per y. We are simboled square root of 2 is rational with p and statement of integer of x per y not zero so square root of 2 equals x per y with q, thus implication can be written with pèq, thus q wrong or –q right, because –qè-p equivalen with pèq, thus we get conclusion that p is wrong or square root of 2 is irrational number.
C. abc formula
a times x square plus b times x plus c equals zero is quadratic equation, so to find a roots of quadratic equation can search with abc formula.
This formula:
a times x square plus b times x plus c equals zero then both of articulations is overed with a.
Become:
x square plus b over a in bracket times x plus c over a equals zero.
Then c over a is transferred to right articulations and both of articulation plus with b over 2a in bracket square.
Become:
x square plus b over a in bracket times x plus b over 2a in bracket square equals b over 2a in bracket square minus c over a.
Then left articulation we can changed to perfect quadratic, become:
x plus b over 2a all in bracket square, then become:
x plus b over 2a all in bracket square equals b square over 4 times a square in bracket minus c over a, then right articulation equation of denominator become:
b square minus 4ac all over open bracket4 times a square close bracket, then become:
x plus b over 2a all in bracket square equals b square minus 4ac all over open bracket 4 times a square close bracket. Then both of articulation we root become:
x plus in bracket b over 2a close bracket equals plus minus square root of b square minus 4acall over open bracket 4 times a square close bracket.
Then we transfer b over 2a to right articulations, become:
x equals minus b over 2a plus minus square root of open bracket b square minus 4ac close bracket all over 2a.
So, x equals minus b plus minus square root of open bracket b square minus 4ac close bracket all over 2a.
D. Point of intersection
Find intersection of y equals x square minus 1 and y square plus x square equals 30.
Solving:
y square plus x square equals 30 is a circle has a radius of square root of 30 and centered in point (0,0) and y equals x square minus 1 is quadratic equation has vertex of -1. For to find a point of intersection we must to substitution y equal x square minus 1 to equation of y square plus x square equals 30.
è y equals x square minus 1 become y plus 1 equals x square then this equation we substitution to y square plus x square equals 30, become:
y square plus y plus 1 equals 30, then 30 we transfer to left articulation become:
y square plus y plus 1 minus 30 equals zero
y square plus y minus 29 equals zero
Then, we find y variable with abc formula, become:
y equals minus 1 plus minus square root of open bracket 1 minus 4 times 1times minus 29 close bracket all over 2
y equals minus 1 plus minus square root of 117 all over 2,
so, y1 equals minus 1 plus square root of 117 all over 2
y1 equals minus 1 plus 10 point 81 all over 2 equals 9 point 81 all over 2 equals 4 point 905
y2 equals minus 1 minus square root of 117 all over 2
y2 equals minus 1 minus 10 point 81 all over 2 equals minus 5 point 905
For y1 equals 4 point 905, we substitution to x square equals y plus 1, become:
x square equals 4 point 905 plus 1
x square equals 5 point 905
x equals plus minus 2 point 43
For y2 equals minus 5 point 905, we substitution to x square equals y plus 1, become:
x square equals minus 5 point 905 plus 1
x square equals minus 4 point 905, because x square minus so this not valid.
So, point of intersection are 2 point 905 comma 4 point 905 and minus 2 point 905 comma 4 point 905.