when the sun is ay certain angles in the sky a 50 foot building casts a 20 foot shadow, what is the length of the shadow in feet cast by a flag pole 20 feet at the same time?

Hope this helps.

correct answer:

i^31 = -i

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this