एक वर्ग आव्यूह (square matrix) सममित आव्यूह (symmetric matrix) कहलाता है यदि वह अपने किसके बराबर होता है?

The 'Drain of Wealth' theory was propounded by which Indian nationalist leader?

Which event is considered the turning point in Mahatma Gandhi's leadership in the Indian independence movement?

Which African leader is known for his non-violent opposition to colonial rule?