Question

What is the value of x in cos(4x-10)=0

Answer 1

cos(4x-10) = 0
⇒ 4x - 10 = 90°
⇒ 4x = 90 + 10
⇒ 4x = 100°
⇒ x = 100°/4
⇒ x = 25°

x is 25°.

Answer 2

cos 90=0.
Therefore, 4x-10=90.
4x=100.
x=100/4
=25 degree.

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