Calculate 1 × 4 / 1 + 4 × 7 / 1 + 7 × 10 / 1 + 10 × 13 / 1 +... 2008 × 2010 / 1

Calculate 1 × 4 / 1 + 4 × 7 / 1 + 7 × 10 / 1 + 10 × 13 / 1 +... 2008 × 2010 / 1

1 × 1 / 4 + 4 × 1 / 7 + 7 × 1 / 10 + 10 × 1 / 13 +... 2008 × 1 / 2011
=（1-1/4+1/4-1/7+1/7-1/10+1/10-1/13+.+1/2005-1/2008+1/2008-1/2011）÷3
=（1-1/2011）÷3
=2010/2011÷3
=670 in 2011

Calculate 1 × 4 / 1 + 4 × 7 / 1 + 7 × 10 / 1 + +1 / 2002 × 2005 + 1 / 2005 × 2008 is calculated by a simple method,

1 × 4 / 1 + 4 × 7 / 1 + 7 × 10 / 1 + +1 / 2002 × 2005 + 1 / 2005 × 2008
=（1-1/4+1/4-1/7+1/7-1/10+…… +1/2002-1/2005+1/2005-1/2008）÷3
=（1-1/2008）÷3
=2007/2008÷3
=669/2008

1/1*4+1/4*7+1/7*10+.1/2002*2005+1/2005*2008

1/1*4+1/4*7+1/7*10+.1/2002*2005+1/2005*2008
=（1-1/4+1/4-1/7+1/7-1/10+…… +1/2002-1/2005+1/2005-1/2008）÷3
=（1-1/2008）÷3
=2007/2008÷3
=669/2008

What is sin ^ 2A + cos ^ 2A = Tan ^ 2A + 1?

The result is wrong
It should be sin & # 178; a + cos & # 178; a = 1