Question

Cot 15 cot 20 cot70cot75 का मान कितना होगा

Answer 1

Answer:

$cot \: {15}^{0} \: cot \: {20}^{0} \: cot \: {70}^{0} \: cot \: {75}^{0} \: \\ = tan( {90}^{0} - {15}^{0} ) \: tan( {90}^{0} - {20}^{0} ) \: cot \: {70}^{0} \: cot \: {75}^{0} \: \\ = tan \: {75}^{0} \times \: tan \: {70}^{0} \: \times \frac{1}{tan \: {70}^{0} } \times \frac{1}{tan \: {75}^{0} } \\ =( tan \: {75}^{0} \times \: \frac{1}{tan \: {75}^{0} } )\: \times (tan \: {70}^{0} \: \times \frac{1}{tan \: {70}^{0} } )\: \\ 1 \: \times 1 \\ = 1$