Question

If P and Q are the roots of the quadratic equation X2 + X - 1 = 0, find the value of 1/P + 1/Q.

Answer 1

1/P + 1/Q = (P+Q) / PQ

Now as P and Q are the roots of the given equation,

P+Q = -b/a = -1

PQ = c/ a = -1

Putting values in _(i)

1/P + 1/Q = 1

Answer 2

1/P + 1/Q = (P+Q) / PQ

Now as P and Q are the roots of the given equation,

P+Q = -b/a = -1

PQ = c/ a = -1

Putting values in _(i)

1/P + 1/Q = 1