Write the correct alternative in the following:

If

Then the value of a_r, 0 < r ≤ n, is equal to

Write the correct alternative in the following:

If x = f(t) cos t – f’(t) sin t and y = f(t) sin t + f’(t) cos t, then

Write the correct alternative in the following:

If y^1/n + y^–1/n = 2x, then (x² – 1)y₂ + xy₁ =

Write the correct alternative in the following:

If y = x^n–1 log x, then x² y₂ + (3 – 2n) xy₁ is equal to

Write the correct alternative in the following:

If xy – log_e y = 1 satisfies the equation x(yy₂ + y₁²) – y₂ + λyy₁ = 0, then λ =