मराठी

Let f: X → Y be an invertible function. Show that f has unique inverse. (Hint: suppose g_1 and g_2 are two inverses of f. Then for all y ∈ Y, fog_1(y) = I_Y(y) = fog_2(y). Use one-one ness of f).

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प्रश्न

Let f: X → Y be an invertible function. Show that f has unique inverse. (Hint: suppose g1 and g2 are two inverses of f. Then for all y ∈ Y, fog1(y) = IY(y) = fog2(y). Use one-one ness of f).

बेरीज
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उत्तर

Let f: X → Y be an invertible function.

Also, suppose f has two inverses (say g1 and g2).

Then, for all y ∈ Y, we have:

fog1(y) = Iy(y) = fog2(y)

⇒ f(g1(y)) = f(g2(y))   ...[f is invertible ⇒ f is one-one]

⇒ g1 = g2    ...[g is one-one]

Hence, f has a unique inverse.

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