In a Triangle ABC,C = 90 then the equation whose roots are TanA, TanB is
Answers
Given:
In a Triangle ABC,C = 90
To find:
The equation whose roots are TanA, TanB is
Solution:
From given, we have,
The sum of angles of a triangle,
A + B + C = 180
Given, C = 90
A + B + 90 = 180
A + B = 90
tan (A + B) = tan A + tan B / 1 - tan A × tan B
as A + B = 90, we get,
tan 90 = tan A + tan B / 1 - tan A × tan B
1 / 0 = tan A + tan B / 1 - tan A × tan B
1 - tan A × tan B = 0
∴ tan A × tan B = 1
the quadratic equation,
x² + sum of roots x + product of roots = 0
x² - (tan A + tan B)x + tan A × tan B = 0
tan A = a/b and tan B = b/a
tan A + tan B = a/b + b/a = (a²+b²)/ab
(a² + b² = c²) Pythagoras theorem.
∴ tan A + tan B= c²/ab
x² - (tan A + tan B)x + tan A × tan B = 0
x² - (c²/ab)x + 1 = 0
abx² - c²x + ab = 0
Therefore, the required equation is, abx² - c²x + ab = 0
Step-by-step explanation:
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