-1=k1+k2 5=3k1+k2/3

-1=k1+k2 5=3k1+k2/3

Because - 1 = K1 + K2
So if K1 = - 1-k2 is replaced by 5 = 3k1 + K2 / 3, then 5 = 3 (- 1-k2) + K2 / 3
So we can get K2 = - 3
Then K1 = - 1-k2 = 2

What formula is K1 '* K2 = - 1

The vertical formula of two straight lines with slope

k1*k2=-1 k1*2=-1 k1=

-1/2

How to transform cos (K1) + cos (K2) + cos (K1 + K2) into a cos

The sum difference product formula cosa + CoSb = 2cos (a + b) / 2cos (a-b) / 2cosa CoSb = - 1 / 2Sin (a + b) / 2Sin (a-b) / 2cos (K1) + cos (K2) + cos (K1 + K2) = 2cos [(K1 + K2) / 2] cos [k1-k2) / 2] + 2cos & # 178; [(K1 + K2) / 2] - 1 = 2cos [(K1 + K2) / 2] {cos [(k1-k2) / 2] + cos [(k