direct and inverse proportion
Post on 12-Apr-2017
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Name – Ankit GoelClass – VIII FRoll No. – 4
Given To:-Mrs. Sandhya
Khera
Direct and Inverse Variation
Direct VariationWe have Direct Variation, if the two variables change in the same sense, that is, if one increases, so does the other.An increase or decrease in one quantity with a corressponding increase or decrease in another quantity such that the ratio remains constant is direct variation.
Example:If y varies directly as xand y = 10 as x =2.4,find x when y = 15.What x and y go together?
Direct Variation
If y varies directly as x and y = 10find x when y = 15.
y = 10, x = 2.4make these y1 and x1
y = 15, and x = ?make these y2 and x2
Direct Variation
Inverse VariationWhen two quantities vary inversely, an increase in one leads to the decrease in the other quantity and vice-versa, in inverse ratio.We have inverse variation if one going up causes the other to go down. An example of this might be speed and time to do a particular journey.
With Direct variation wedivide our x’s and y’s.
In Inverse variation we willmultiply them.
x1y1 = x2y2
Inverse Variation
If y varies inversely with x andy = 12 when x = 2, find y when x = 8
x1y1 = x2y2
2(12) = 8y24 = 8y
y = 3
Inverse Variation
If y varies inversely as x and x = 18When y = 6, find y when x = 8.
18(6) = 8y 108 = 8y y = 13.5
Inverse Variation
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