Question
Question: If x sin (α + y) = sin y and y′ = \(\frac{m}{(x^{2} + 2nx + 1)}\), then...
If x sin (α + y) = sin y and y′ = (x2+2nx+1)m, then
A
m – n = 1
B
m + n = 1
C
m2 + n2 = 1
D
m = n
Answer
m2 + n2 = 1
Explanation
Solution
tan y = 1−xcosαxsinα
On differentiating wrt x, we get
dxdy= (1−xcosα)sinα
⇒ m = sin α, n = – cos α
∴ m2 + n2 =1