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Application Of Derivatives

Question
CBSEENMA12035154

Find the equation of the tangent to the curve x2 + 3y = 3, which is parallel to the line y – 4x + 5 = 0. 

Solution

The equation of curve is x2 + 3y = 3                               ...(1)
Differentiating w.r.t.x, we get,
2 straight x plus 3 dy over dx space equals 0 space space space space rightwards double arrow space space space space dy over dx space equals space minus fraction numerator 2 straight x over denominator 3 end fraction
therefore space space space straight m subscript 1 space equals space minus fraction numerator 2 straight x over denominator 3 end fraction
Let space space straight m subscript 2 space be space slope space of space line space space straight y minus 4 straight x plus 5 space equals space 0
therefore space space space space space space straight m subscript 2 space equals 4
because space space space tangent space is space parallel space to space straight y minus 4 straight x plus 5 space equals space 0
therefore space space space space space space straight m subscript 1 space equals space straight m subscript 2
therefore space space space space space space space fraction numerator negative 2 straight x over denominator 3 end fraction space equals space 4 space space space space space space space space space space space space space space space space space rightwards double arrow space space space straight x space equals space minus 6
therefore space space space space space space from space left parenthesis 1 right parenthesis comma space space space 36 plus 3 straight y space equals space 3 space space space space rightwards double arrow space space space space straight y space equals space minus 11
therefore space space space point space is space left parenthesis negative 6 comma space minus 11 right parenthesis
therefore space space space space equation space of space tangent space at space left parenthesis negative 6 comma space minus 11 right parenthesis space is
space space space space space straight y plus 11 space equals space 4 left parenthesis straight x plus 6 right parenthesis space space space space or space space space space space space straight y plus 11 space equals space 4 straight x plus 24 space space space space space or space space space space 4 straight x minus straight y plus 13 space equals space 0