Quizzes & Puzzles3 mins ago
Maths solving simultaneous equations using graphs
here is the question:
1.a)draw the graph of x^2 + y^2 = 25 and y = x + 1 on the same grid.
b) Use the graph to solve simultaneously the two equations.
is it allowed to plot the graph (after rearranging the formula) y = square root of 2 - x^2 (there isnt a square root key on the keyboard lol)
please help asap
thanx
xx
Answers
No best answer has yet been selected by *mystical*. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.Another approach is to get the 2 equations looking similar and then add or subtract them from each other. I'm sure there's a technical term for this but :
x� + y� = 25 or y� = 25 - x�
and
y=x+1 or y� = (x+1)�
start to look similar, in that you've isolated the y� part.
y� = x� + 2x +1 (which, if you introduce the first equation, is equal to 25-x� )
25 - x� = x� + 2x + 1
0 = 2x� + 2x - 24 (divide by 2)
gives (x+3)(x-4) so x=3 (which makes y=4)
and x= -4 (and thus y=-3)
When you have a graph with axes x & y you cannot 'plot' y� as such so you need to rearrange it into the form y = ... so that for every value of x you put into the equation you get the corresponding value for y, with each pair x,y being a point on the graph.
You can also place as many equations as you find practical on one graph.
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