Question

what is the value of Cos(π+x)​

Answer 1

$\huge\bold{\gray{\sf{Answer:}}}$

Explanation:

The value of $\bold{\red{Cos(π+x) }}$is $\bold{\red{-cos x}}$

Reason :

The cos(π-x) will lie in second quadrant and in 2nd quadrant Cos is negative.

Concept :

• In 1st quadrant all trigonometric ratio is positive
• In 2n quadrant sin and cosec is positive and cos,sec,tan & cot are negative
• In 3rd quadrant Tan and cot is positive and sin,cosec,cos and sec are negative
• In 4th quadrant Cos and sec is positive ans sin,cosec ,tan ans cot are negative

Tricks to learn this table :

• Add :-All positive
• sugar -sin
• To -Tan
• Coffee-Cos

Remember:

• Sin and cos repeat its value after an interval of 2π
• The trigonometric value changed only at 90°and 270°