1.The value of tan−1(13)+tan−1(15)+tan−1(17)+tan−1(18)\tan^{-1} \left(\frac{1}{3}\right) + \tan^{-1} \left(\frac{1}{5}\right) + \tan^{-1} \left(\frac{1}{7}\right) + \tan^{-1} \left(\frac{1}{8}\right)tan−1(31)+tan−1(51)+tan−1(71)+tan−1(81) isa.4π3\frac{4\pi}{3}34πb.π4\frac{\pi}{4}4πc.2π4\frac{2\pi}{4}42πd.3π4\frac{3\pi}{4}43πLogin to continueOnly logged in users canattempt or see the solution.