If x=∑(-1)^n tan²nθ and y=∑cos²nθ... | Sequences and Series

JEE MAIN 2020

09-01-2020 S2

Question

$\begin{aligned} & \text { If } x=\sum_{n=0}^{\infty}(-1)^n \tan ^{2 n} \theta \text { and } y=\sum_{n=0}^{\infty} \cos ^{2 n} \theta \\ & \text
{ for } 0<\theta<\frac{\pi}{4} \text {, then }\end{aligned}$

Select the correct option:

x(1 – y) = 1

y(1 + x) = 1

y(1 – x) = 1

x(1 + y) = 1

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

Question Tags

JEE Main

Mathematics

Easy

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