Question

cos (3x+15)=0 find x​

Answer 1

cos(3x+15)=0

cos(3x+15)=cos90

3x+15=90

3x=90-15

3x=75

x=75/3

x=30°

Answer 2

Step-by-step explanation:

correct answer is that

3x+15=π/2±(x+45)+2nπ3x+15=π/2±(x+45)+2nπ

so, x=((2n+1/2)π+30)/2=15+/pi/4+nπx=((2n+1/2)π+30)/2=15+/pi/4+nπ

or x=((2n+1/2)π−60)/4=−15+nπ/2

So, if the problem had been to solve for xx in SIN(3x+15)∘=COS(x+45)∘SIN(3x+15)∘=COS(x+45)∘ ,

then it would be correct to say that

3x+15=90±(x+45)+360n3x+15=90±(x+45)+360n

so x=((360n+90)+30)/2=60+180nx=((360n+90)+30)/2=60+180n

or x=((360n+90)−60)/4=7.5+90n