1: \(A=sin10^0+sin40^0-cos50^0-cos80^0\)
\(=\left(sin10^0-cos80^0\right)+\left(sin40^0-cos50^0\right)\)
\(=\left(sin10^0-sin10^0\right)+\left(sin40^0-sin40^0\right)\)
=0+0=0
2: \(B=cos15^0+cos35^0-sin55^0-sin75^0\)
\(=\left(cos15^0-sin75^0\right)+\left(cos35^0-sin55^0\right)\)
\(=\left(cos15^0-cos15^0\right)+\left(cos35^0-cos35^0\right)\)
=0+0=0
3: \(C=sin^215^0+sin^235^0+sin^255^0+sin^275^0\)
\(=\left(sin^215^0+sin^275^0\right)+\left(sin^235^0+sin^255^0\right)\)
\(=\left(sin^215^0+cos^215^0\right)+\left(sin^235^0+cos^235^0\right)\)
=1+1=2
4: \(D=cos^215^0+cos^235^0+cos^255^0+cos^275^0\)
\(=\left(cos^215^0+cos^275^0\right)+\left(cos^235^0+cos^255^0\right)\)
\(=\left(cos^215^0+sin^215^0\right)+\left(cos^235^0+sin^235^0\right)\)
=1+1
=2
5: \(E=cos^281^0+cos^29^0-5\cdot cot62^0\cdot cot28^0\)
\(=cos^281^0+sin^281^0-5\cdot tan28\cdot cot28\)
=1-5=-4
6: \(F=sin^272^0+cos^272^0+2\cdot\dfrac{tan55}{cot35}\)
=1+2
=3
7: \(G=cot33^0+sin^225^0-tan57^0+sin^265^0-5\cdot\dfrac{tan24}{cot66}\)
\(=\left(cot33^0-tan57^0\right)+\left(sin^225^0+sin^265^0\right)-5\cdot\dfrac{cot66}{cot66}\)
=0+1-5
=-4
