sin⁻¹(4/5) + cos⁻¹(2/√5) = কত?

ব্যাখ্যা

sin⁻¹(4/5) + cos⁻¹(2/√5) = tan⁻¹(4/3) + tan⁻¹(1/2) = tan⁻¹{(4/3 + 1/2)/(1 − (4/3)(1/2))} = tan⁻¹{(11/6)/(2/6)} = tan⁻¹(11/2)