Posts

Showing posts from February, 2008

The Log-Antilog Procedure: Part II

Not too long later, I learned in additional mathematics, certain trigonometric identities of the form cos(A ± B) = –(cos A cos B ± sin A sin B), from which we can form another identity: cos A cos B = ½ [cos(A + B) + cos(A – B)].

This identity is the basis of an obsolete technique known as prosthaphaeretic multiplication, which is very similar but older than the log-antilog procedure taught by my teacher. To illustrate prosthaphaeretic multiplication on 10.8 x 87.85, we proceeds as follows: First write 10.8 x 87.85 as 0.108 x 0.8785 x 10000, then read the arccosine values for 0.108 and 0.8785 from table, they are 1.463 and 0.498 in radians. With the identity, multiplication of two cosines is converted to addition/subtraction of their respective arccosines, that is,

10.8 x 87.85 = cos 1.463 x cos 0.498 x 10000 = ½[cos(1.463 + 0.498) + cos(1.463 - 0.498)] x 10000

The result is 945, which is very close to the exact solution: 948.78.

At the time, I thought, the only sensible reason for retain…

Professor Nik Hassan Shuhaimi Nik Abdul Rahman: Part I

I came across a rather harsh commentary by Prof. Wilhelm G. Solheim II on a recent JMBRAS article written by Prof. Nik Hassan Shuhaimi, to which Prof. Nik replied bitterly in seven points.

Therefore, I decided to run a quick biographical check on both Prof Nik and Prof. Solheim.

Nik Hassan Shuhaimi Nik Abdul Rahman is currently the president of the Association Malaysian Archeologists. Academically, he is with the Institute of the Malay World and Civilization in Universiti Kebangsaan Malaysia (UKM).

Prof. Nik was born February 4, 1944. He received his early education in Malay School Kubang Keranji, Kota Bharu and the famous Malay College Kuala Kangsar. Between 1962 and 1963, he went to study in Technical College, Kuala Lumpur. In 1965, he was admitted to the Malayan Teachers College in Penang. After obtaining his teaching certificate, he returned to Kelantan and taught in Kubang Kerian Secondary School for about 4 years.

After the riot in May 1969, he was admitted to the University of Mala…