Question

answer correctly plz it is imp​

Answer 1

Answer:

Since, cos= Base /perpendicular

so, according to the question:

cos=4x/1

from Pythagoras theorem:

H²=B²+P²

P=√H²-B²

P=√1²-4x²

P=1-16x

P= -15x

So, hypotenuse is 1

perpendicular is -15x

and base is 4x

therefore let us prove that cos4x= 1-8 sin²x cos²x

4x/1= -7*-15x/1*4x/1

4x/1 =420x

105 is the answer

Proved..