If x = et cost and y = et sint, then what is  at t = 0 equal to?

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NDA (Held On: 18 Apr 2021) Maths Previous Year paper
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  1. 0
  2. 1
  3. 2e
  4. -1

Answer (Detailed Solution Below)

Option 2 : 1
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NDA 01/2025: English Subject Test
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Detailed Solution

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CONCEPT:

Parametric Differentiation:

If x = f(t), y = g(t), where t is a parameter, then 

CALCULATION:

Given: x = et cost and y = esint

First let's find out dx/dt

⇒ 

Now let's find out dy/dt

⇒ 

⇒ 

⇒ 

Hence, correct option is 2.

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