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Application Of Derivatives

Question
CBSEENMA12035878

Find the equation of the tangent to the curve y = 3x - 2 which is parallel to the line 4x – 2y + 5 = 0

Solution

Curve  y =  3x - 2dy dx = 12  3x - 2 -12 x 3 dy dx = 32   3x - 2           .........(i)

Since, the tangent is parallel to the line  4x - 2y = - 5

Therefore, slope of tangent can be obtained from equation

y = 4x2 + 52Slope = 2 dydx = 2                               ...........(ii)

Comparing  equations (i)  and (ii), we have,

32 x 1 3x - 2 = 2 1 3x - 2 = 43  1 3x - 2 = 169 9 = 48x - 32 x = 4148We have,   y =  3x - 2

Thus, substituting the value of x in the above euation,

     y =  3 x 4148 - 2 y =   4116 - 2 y =   41 - 3216   y =   916   y = 34

Equation of tangent is

      y - 34  = 2  x - 4148  y - 34  = 2x - 4124  y = 2x - 4124 + 34 y = 2x - 4124 + 1824  y = 2x - 2324 24y = 48x - 23 48x - 24y - 23 = 0