2cos2x=y
dy/dx(2cos2x)=-4sin2x
d/du cosu= u'×cos'u=-u'×sinu
d/du sinu= u'×sin'u= u'×cosu
d/du tanu = u'×(1+tan²u)
d/du cotu = u'×-(1+cot²u)
proof for cosu :
cos2x= 1-2sin²x
or 2cosx²-1
or cos²x-sin²x
we will one of this fro example let's take the first one
d/dx 1-2sin²x=0-2×2(sinx)×cosx=-2sin2x
and we have 2 in the begining so its -4sin2x
Multiply 45 by 2/3 2/3 = 0.66666 so 45*0.6666 = 30
It is 12/b: opposite/adjacent
Less because if you multiply any number by a fraction (not mixed or improper) than it will always be less because multiplying it by 1 will keep it the same anything less than one will make the number smaller the answer of 3/4 x 2/9 is 1/6 btw
