1.If x∈Rx \in \mathbb{R}x∈R, the numbers (51−x+51+x)\bigl(5^{1-x} + 5^{1+x}\bigr)(51−x+51+x), a2\dfrac{a}{2}2a, (25x+25−x)\bigl(25^x + 25^{-x}\bigr)(25x+25−x) form an A.P., then aaa must lie in the intervala.[1,5][1, 5][1,5]b.[2,5][2, 5][2,5]c.[5,12][5, 12][5,12]d.[12,∞)[12, \infty)[12,∞)Login to continueOnly logged in users canattempt or see the solution.
