For the following questions answer them individually
If $$R = \left\{(a, b) \epsilon R^{2} : a - b + \sqrt{2}\right\}$$ is irrational then the relation R on $$R^{2}$$ is:
If f(1) = 1 and $$f(n) = 2 \sum_{k-1}^{n-1} f(k),(n > 1)$$ then $$\sum_{k-1}^{m} f(k)$$ =
A line l passing through the point (1, -2) is perpendicularto the line x+2y+1=0. Thenthe point of intersection of 1 and x + 2y + 1 = 0 1s:
$$\frac{\cos \theta}{7} = \frac{\sin \theta}{6} \Rightarrow 7 \cos 2 \theta + 6 \sin 2 \theta = $$