For set P, sin‌θ−cos‌θ=√2‌cos‌θ‌ ⇒tan‌θ−1=√2 [dividing both sides by cos‌θ] ⇒tan‌θ=√2+1 .......(i) For set Q sin‌θ+cos‌θ=√2‌sin‌θ‌ ⇒1+cot‌θ=√2 [dividing both sides by sin‌θ] ⇒cot‌θ=√2−1 ⇒tan‌θ=√2+1 .........(ii) Hence, P=Q‌‌‌ [from Eqs. (i) and (ii)]